/*
* Copyright 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "sgabios.h"
#define BUILD_CL "$Id$"
.code16
.text
.section ".init","ax"
.globl _start
.type _start,@object
_start:
/* option rom header */
.byte 0x55
.byte 0xaa
.byte _rom_size_byte
.size _start, .-_start
.globl legacy_entry
.type legacy_entry,@function
legacy_entry:
jmp sga_init
/* pnp entry here to avoid changing PnP table as code moves */
pnp_init:
jmp pnp_sga_init
/*
* do_old_int10h
*
* Patched at option rom init to be a far jump to old int 10h isr
*
*/
do_old_int10h:
.byte 0xea /* jmp absolute segment:offset */
old_int10h: /* store what was at offset 0x40 */
.word 0xf065 /* placeholder for chained ISR offset */
/* if the chained segment is detected as 0xc000, use 80 cols only */
/* since it's assumed that a vga card is attached and 80 cols max */
old_int10h_seg:
.word 0xf000 /* placeholder for chained ISR segment */
/*
* do_old_int16h
*
* Patched at option rom init to be a far jump to old int 16h isr
*
*/
do_old_int16h:
.byte 0xea /* jmp absolute segment:offset */
old_int16h: /* store what was at offset 0x58 */
.word 0xe82e /* placeholder for chained ISR offset */
.word 0xf000 /* placeholder for chained ISR segment */
.org 0x18
.word 0 /* offset to PCI data, 0 = none */
.word pnp_table /* offset to PnP expansion header */
.org 0x20
pnp_table:
/* FIXME: **** PnP header currently disabled by PoO **** */
/* legacy entry only called once, PnP entry called multiple times */
/* The code isn't yet written to deal with multiple inits properly */
.ascii "$PoO" /* PnP expansion header signature */
.byte 1 /* structure revision */
.byte 2 /* length in 16-byte increments */
.word 0 /* offset of next header, 0 if none */
.byte 0 /* reserved */
.byte 0x52 /* checksum - update manually! FIXME */
.long 0 /* device identifier */
.word mfg_string /* pointer to manufacturer string */
.word prod_string /* pointer to product name string */
.byte 3, 0x80, 0x80 /* device type code = other display */
.byte 0xe3 /* device indicators, kbd/display dev */
.word 0 /* boot connection vector, 0 if none */
.word 0 /* disconnect vector, 0 if none */
.word pnp_init /* bootstrap entry vector */
.word 0 /* reserved */
.word 0 /* static resource information vector */
/* WARNING: changing mfg_string / prod_string locations will */
/* affect pnp table above -- recalculate checksum manually! */
mfg_string:
.asciz "Google, Inc."
prod_string:
.ascii "Serial Graphics Adapter "
build_date:
.asciz BUILD_SHORT_DATE
long_version:
.ascii "SGABIOS "
.ascii BUILD_CL
.ascii " ("
.ascii BUILD_USER
.ascii "@"
.ascii BUILD_HOST
.ascii ") "
.asciz BUILD_DATE
term_cols:
.byte 80 /* overwritten at rom init with detected value */
term_rows:
.byte 24 /* overwritten at rom init with detected value */
term_init_string: /* terminal reply: \033[n;mR n=row, m=col */
.asciz "\033[1;256r\033[256;256H\033[6n"
/* reset the scroll, move to col 256, row 256, ask current position */
/* bios cursor positions >255 rows or cols can't be used anyway */
term_info:
.asciz "Term: "
ebda_info:
.asciz "EBDA: "
/*
* do_old_irq3 - exception 0x0b, int 0x0a
*
* Patched at option rom init to be a far jump to old irq 3 isr
*
*/
do_old_irq3:
.byte 0xea /* jmp absolute segment:offset */
old_irq3: /* store what was at offset 0x28 */
.word 0xeef3 /* placeholder for chained ISR offset */
.word 0xf000 /* placeholder for chained ISR segment */
/*
* do_old_irq4 - exception 0x0c, int 0x0b
*
* Patched at option rom init to be a far jump to old irq 4 isr
*
*/
do_old_irq4:
.byte 0xea /* jmp absolute segment:offset */
old_irq4: /* store what was at offset 0x2c */
.word 0xeef3 /* placeholder for chained ISR offset */
.word 0xf000 /* placeholder for chained ISR segment */
/*
* do_old_int14h
*
* Patched at option rom init to be a far jump to old int 14h isr
*
*/
do_old_int14h:
.byte 0xea /* jmp absolute segment:offset */
old_int14h: /* store what was at offset 0x50 */
.word 0xe739 /* placeholder for chained ISR offset */
.word 0xf000 /* placeholder for chained ISR segment */
.align 16, 0xff /* aligning this table only makes hexdump prettier */
/* ascii -> scancode, bit 7=shifted, char < 32 = +ctrl */
/* except chars 8, 9, 13, 27 (bs, tab, enter, esc) */
/* most int16h consumers will probably never use */
ascii2scan:
/*00*/ .byte 0x00, 0x1e, 0x30, 0x2e, 0x20, 0x12, 0x21, 0x22
/*08*/ .byte 0x0e, 0x17, 0x24, 0x25, 0x26, 0x1c, 0x31, 0x18
/*10*/ .byte 0x19, 0x0f, 0x13, 0x1f, 0x14, 0x16, 0x2f, 0x11
/*18*/ .byte 0x2d, 0x15, 0x2c, 0x01, 0x2b, 0x1b, 0x87, 0x8c
/*20*/ .byte 0x39, 0x82, 0xa8, 0x84, 0x85, 0x86, 0x88, 0x28
/*28*/ .byte 0x8a, 0x8b, 0x89, 0x8d, 0x33, 0x0c, 0x34, 0x35
/*30*/ .byte 0x0b, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08
/*38*/ .byte 0x09, 0x0a, 0xa7, 0x27, 0xb3, 0x0d, 0x34, 0xb5
/*40*/ .byte 0x83, 0x9e, 0xb0, 0xae, 0xa0, 0x92, 0xa1, 0xa2
/*48*/ .byte 0xa3, 0x97, 0xa4, 0xa5, 0xa6, 0xb2, 0xb1, 0x98
/*50*/ .byte 0x99, 0x90, 0x93, 0x9f, 0x94, 0x96, 0xaf, 0x91
/*58*/ .byte 0xad, 0x95, 0xac, 0x1a, 0x2b, 0x1b, 0x87, 0x8c
/*60*/ .byte 0x29, 0x1e, 0x30, 0x2e, 0x20, 0x12, 0x21, 0x22
/*68*/ .byte 0x23, 0x17, 0x24, 0x25, 0x26, 0x32, 0x31, 0x18
/*70*/ .byte 0x19, 0x10, 0x13, 0x1f, 0x14, 0x16, 0x2f, 0x11
/*78*/ .byte 0x2d, 0x15, 0x2c, 0x9a, 0xab, 0x9b, 0xa9, 0x0e
/* TABLES FOR NON-ASCII VGA CHARACTERS (CP437) TO ASCII */
/* Unicode at: http://en.wikipedia.org/wiki/Code_page_437 */
ctrl2ascii:
/* translate vga (CP437) first 32 characters to ascii */
/* for char 0, update the cursor position, but output nothing */
/* lilo uses this "trick" for a background attribute update */
.ascii "\0@@v***........*><|!PS-|^v><L-^v"
high2ascii:
/* translate vga (CP437) chars 0x80 to 0xff to ascii */
/* these characters are mostly to visually approximate */
/* line art characters will probably need tweaking */
/*80*/ .ascii "CueaaaaceeeiiiAAEaAooouuyOUcLYPf"
/*a0*/ .ascii "aiounNao?--24!<>###||||++||+++++"
/*c0*/ .ascii "+--|-+||++--|-+----++++++++#-||-"
/*e0*/ .ascii "abgpesut00osiye^=+><||-=...vn2* "
colortable:
/* vga text color is IRGB, ansi color is BGR */
/* this table is effectively a nibble bit-reverse */
.byte 0, 4, 2, 6, 1, 5, 3, 7
serial_port_base_address:
.word COM_BASE_ADDR
/* in-memory console log
*
* It's expected that the EBDA contains a magic signature
* like 0xdeadbabe, followed by a byte of flags, followed
* by a 32-bit buffer pointer, followed by a 16-bit start
* index, followed by a 16-bit end index, followed by 16-
* bit logged character count, followed by an 8-bit flag.
*/
#define MEMCONSOLE_BUFFER_SIZE 32768
#define MEMCONSOLE_SIGNATURE 0xdeadbabe
#define MEMCONSOLE_ENDINDEX_OFF 0x0b
#define SGABIOS_EBDA_SIGNATURE 0x00414753
memconsole_buffer_start: /* pulled from ebda struct */
.long 0x00000000 /* 0 = not found/no logging */
memconsole_ebda_deadbabe_offset: /* bytes from start of ebda */
.word 0x0000 /* 40:0e contains ebda seg */
sgabios_ebda_logbuf_offset: /* bytes from start of ebda */
.word 0x0000 /* 40:0e contains ebda seg */
/*
* setup_memconsole
*
* Initialize the option rom variables associated with logging
* of the legacy console output
*
* If these variables are left at zero, no logging will occur
*
* There are no parameters
* All registers except flags should be preserved
*/
setup_memconsole:
pushaw
pushw %ds
pushw %es
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
pushw BDA_EBDA /* push word at 0x0e */
popw %es /* es = EBDA_SEG */
/* search for memconsole signature in ebda */
movl $MEMCONSOLE_SIGNATURE, %eax
xorw %di, %di /* start at zero */
movzbw %es:(%di), %cx /* cx = size of EBDA in KB */
shlw $8, %cx /* cx = (cx * 1024) / 4 */
cld
repnz
scasl /* search until sig found */
subw $4, %di /* scasl always increments di, undo */
cmpl %eax, %es:(%di) /* is signature here? */
jnz setup_memconsole_end /* bail if so */
movw %di, %cs:memconsole_ebda_deadbabe_offset /* save offset */
movl %es:5(%di), %eax /* get 32-bit buffer base address */
movl %eax, %cs:memconsole_buffer_start
setup_memconsole_end:
popw %es
popw %ds
popaw
ret
/*
* memconsole_log_char
*
* Log the character passed in %al to the next available memory
* console log position, if any.
*
* If memconsole_buffer_start is zero, no logging will occur
*
* %al = character to be logged
* All registers except flags should be preserved
*/
memconsole_log_char:
pushaw
pushw %ds
pushw %es
pushw %fs
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
pushw BDA_EBDA /* push word at 0x0e */
popw %es /* es = EBDA_SEG */
movw %ax, %si /* %si = %al = byte to write */
movl %cs:memconsole_buffer_start, %ebp
movw %cs:memconsole_ebda_deadbabe_offset, %di
addw $MEMCONSOLE_ENDINDEX_OFF, %di /* %di points to char pos */
orl %ebp, %ebp
jz memconsole_log_tail /* bufptr==0, no logging */
movw %es:(%di), %bx /* bx = current position in buffer */
cmpw $MEMCONSOLE_BUFFER_SIZE, %bx /* at end of buffer? */
jnc memconsole_log_tail /* don't log any more if so */
cmpb $0xd, %al /* is the char CR? */
jz memconsole_log_tail /* if so, ignore it */
cmpb $0x8, %al /* is the char backspace? */
jnz memconsole_update_fsbase /* if not, log char as usual... */
orw %bx, %bx /* make sure ptr isn't already zero */
jz memconsole_log_tail /* if so, bail */
decw %bx /* else point to previous character */
jmp memconsole_update_end_ptr /* and go directly to save it */
memconsole_update_fsbase:
movl $0xc0000100, %ecx /* ecx = IA32_FS_BASE (AMD64+) */
rdmsr /* read what was there before */
pushl %eax /* save away previous FS_BASE eax */
pushl %edx /* save away previous FS_BASE edx */
xorl %edx, %edx /* clear high 32 bits */
movl %ebp, %eax /* eax = memconsole buffer start */
wrmsr /* fs_base = memconsole buffer start */
movw %si, %ax /* %ax = saved value on entry */
movb %al, %fs:(%bx) /* log character */
popl %edx /* restore previous FS_BASE edx */
popl %eax /* restore previous FS_BASE eax */
wrmsr /* write what was there before */
incw %bx /* update character count */
memconsole_update_end_ptr:
movw %bx, %es:(%di) /* save new end pointer */
addw $2, %di /* numchars stored at next word */
movw %bx, %es:(%di) /* save new numchar value */
memconsole_log_tail:
popw %fs
popw %es
popw %ds
popaw
ret
/* sgabioslog_setup_ebda
*
* SGABIOS makes its own 1KB EBDA allocation to save non-
* translated characters with associated cursor positions
* for the last 256 characters output. This is organized
* with 256 bytes reserved for houskeeping, 256 bytes for
* the raw character codes, and 512 bytes of 16bit cursor
* positions to record the associated position for each.
*
* The first 4 bytes contain "SGA\0" followed by a 16-bit
* size of the allocation in bytes, followed by a 16-bit
* index indicating the next spot to be overwritten.
*
* There are no parameters
* All registers should be preserved
*/
sgabioslog_setup_ebda:
pushf
pushaw
pushw %ds
pushw %es
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movw BDA_EBDA, %ax /* ax = old ebda segment from 0x0e */
subw $SGABIOS_EBDA_DELTA, %ax
movw %ax, %es /* es = new EBDA segment start */
cmpw $EBDA_MIN_SEG, %ax /* is there room for the allocation? */
jc sgabioslog_setup_ebda_tail /* if not, don't change anything */
cli /* paranoid in case irq uses EBDA */
movw %ax, BDA_EBDA /* save new EBDA segment start */
subw $SGABIOS_EBDA_KB, BDA_MEM_SIZE /* subtract extra allocation */
movw %ax, %ds /* ds = new EBDA segment start */
movw $SGABIOS_EBDA_BYTES, %si /* si = offset of first byte to move */
movzbw (%si), %cx /* cx = number of KB in EBDA */
addb $SGABIOS_EBDA_KB, (%si) /* update EBDA size in kb */
shlw $10, %cx /* cx = KB * 1024 = bytes in EBDA */
movw %cx, %cs:sgabios_ebda_logbuf_offset /* new ebda space */
xorw %di, %di /* di = new EBDA start */
cld
rep
movsb /* move ebda by SGABIOS_EBDA_BYTES */
movw %cs:sgabios_ebda_logbuf_offset, %bx /* bx = new buffer */
movl $SGABIOS_EBDA_SIGNATURE, (%bx) /* setup signature */
movw $SGABIOS_EBDA_BYTES, 4(%bx) /* bytes in new ebda buffer */
movw $0, 6(%bx) /* next log index, new ebda buffer */
sgabioslog_setup_ebda_tail:
popw %es
popw %ds
popaw
popf
ret
/*
* sgabioslog_save_char
*
* Like memconsole_log_char, except the original, untranslated
* character is expected to be given in the %al register.
*
* The original character and its corresponding cursor position
* are logged to the sgabios ebda memory allocation.
*
* %al = character to be logged
* All registers except flags should be preserved
*/
sgabioslog_save_char:
pushaw
pushw %ds
pushw %es
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
pushw BDA_EBDA /* push word at 0x0e */
popw %es /* es = EBDA_SEG */
movw %cs:sgabios_ebda_logbuf_offset, %di
orw %di, %di /* is offset zero? */
jz sgabioslog_save_tail /* if so, bail */
cmpl $SGABIOS_EBDA_SIGNATURE, %es:(%di)
jnz sgabioslog_save_tail /* bail if magic not found */
movw %es:6(%di), %bx /* bx = index of next char output */
movb %al, %es:SGABIOS_EBDA_LOG_START(%bx,%di) /* store character */
movzbw %bl, %ax /* %ax = next cursor buffer index */
shlw $1, %ax /* %ax = offset to cursor storage */
call get_current_cursor /* %dh = row, %dl = column */
addw $SGABIOS_EBDA_POS_START, %di /* cursor storage */
addw %ax, %di /* %di = next cursor storage offset */
movw %dx, %es:(%di) /* save position for logged char */
incw %bx /* point to next char to log */
cmpw $SGABIOS_EBDA_LOG_SIZE, %bx
jnz sgabioslog_save_index
xorw %bx, %bx /* wrap around to start */
sgabioslog_save_index:
movw %cs:sgabios_ebda_logbuf_offset, %di
movw %bx, %es:6(%di) /* save new index */
sgabioslog_save_tail:
popw %es
popw %ds
popaw
ret
/*
* sgabioslog_get_char
*
* Return the character at current cursor position, last recorded
* to sgabios ebda allocation, if available.
*
* If the current cursor postition contains one of the last 256 characters
* written to the ebda buffer, return that character, else return 0.
*
* If sgabios_ebdda_logbuf_offset is zero, %al will be 0 and zf set
*
* All registers except flags and %al should be preserved
*/
sgabioslog_get_char:
pushaw
movw %sp, %bp
movb $0, 14(%bp) /* %al on stack = 0 */
pushw %ds
pushw %es
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
pushw BDA_EBDA /* push word at 0x0e */
popw %es /* es = EBDA_SEG */
movw %cs:sgabios_ebda_logbuf_offset, %di
orw %di, %di
jz sgabioslog_get_tail /* offset==0, no logging */
cmpl $SGABIOS_EBDA_SIGNATURE, %es:(%di)
jnz sgabioslog_get_tail /* bail if magic not found */
call get_current_cursor /* dh = row, dl = col */
std /* scan backwards in mem */
movw %es:6(%di), %bx /* bx = index of next char output */
decw %bx /* %bx = offset of last char in buf */
jnc sgabioslog_got_pos
addw $SGABIOS_EBDA_LOG_SIZE, %bx /* bx position wrap around */
sgabioslog_got_pos:
movw %bx, %ax /* %ax = last cursor pos written */
shlw $1, %ax /* %ax = offset of last cursor pos */
addw $SGABIOS_EBDA_POS_START, %di /* %di = first cursor position */
addw %ax, %di /* %di = offset in ebda */
movw %dx, %ax /* %ax = cursor pos to compare */
movw %bx, %cx /* %cx = positions before wrap */
jcxz sgabioslog_cmp_wrap /* if zero, try from end next */
repnz
scasw /* search until position match */
addw $2, %di /* scasd always decrements di, undo */
cmpw %ax, %es:(%di) /* did it really match? */
jz sgabioslog_cursor_match /* if so, do something */
sgabioslog_cmp_wrap:
movw %cs:sgabios_ebda_logbuf_offset, %di
addw $SGABIOS_EBDA_POS_LAST, %di /* %di = last cursor storage */
movw $SGABIOS_EBDA_LOG_SIZE, %cx /* %cx = compare all positions */
repnz
scasw /* search until position match */
addw $2, %di /* scasd always decrements di, undo */
cmpw %ax, %es:(%di) /* did it really match? */
jnz sgabioslog_get_tail /* if not, bail */
sgabioslog_cursor_match:
/* %di contains the EBDA offset of the matching position */
/* convert this into a memconsole offset */
subw $512, %di /* take off the storage offset */
subw %cs:sgabios_ebda_logbuf_offset, %di /* and ebda offset */
shrw $1, %di /* %di = char position index */
addw %cs:sgabios_ebda_logbuf_offset, %di /* add back ebda offset */
addw $SGABIOS_EBDA_LOG_START, %di /* and add back log offset */
movb %es:(%di), %al /* get related saved character */
movb %al, 14(%bp) /* %al on stack = logged char */
sgabioslog_get_tail:
popw %es
popw %ds
popaw
ret
/*
* multibyteinput
*
* When an escape key is detected, the input routines will attempt to
* capture as many characters as arrive up until a timeout, or six,
* whichever is less.
*
* This table is intended to decide what the characters after the
* initial escape key translate to in terms of high and low bytes
* that go into the keyboard buffer the high byte is the scancode,
* the low byte is ascii, but for special keys this is usually 0xe0
* or 0x00.
*
* This table is formatted so that the first word is a scancode +
* ascii pair (as returned by int 16h, ah = 10h or 11h). Immediately
* following is a nul-terminated ascii string to match in order to
* use the corresponding scancode+ascii word.
*
* The search through this table is terminated by a match or finding
* a 0 scancode+ascii word.
*
* FIXME: all the low bytes are now zero, get rid of them?
*/
multibyteinput:
.byte 0x3b /* F1 */
.asciz "[[A" /* F1/screen */
.byte 0x3b /* F1 */
.asciz "OP" /* F1/xterm/ansi */
.byte 0x3b /* F1 */
.asciz "[11~" /* F1/vt400 */
.byte 0x3c /* F2 */
.asciz "[[B" /* F2/screen */
.byte 0x3c /* F2 */
.asciz "OQ" /* F2/xterm/ansi */
.byte 0x3c /* F2 */
.asciz "[12~" /* F2/vt400 */
.byte 0x3d /* F3 */
.asciz "[[C" /* F3/screen */
.byte 0x3d /* F3 */
.asciz "OR" /* F3/xterm/ansi */
.byte 0x3d /* F3 */
.asciz "[13~" /* F3/vt400 */
.byte 0x3e /* F4 */
.asciz "[[D" /* F4/screen */
.byte 0x3e /* F4 */
.asciz "OS" /* F4/xterm/ansi */
.byte 0x3e /* F4 */
.asciz "[14~" /* F4/vt400 */
.byte 0x3f /* F5 */
.asciz "[[E" /* F5/screen */
.byte 0x3f /* F5 */
.asciz "[15~" /* F5/xterm */
.byte 0x3f /* F5 */
.asciz "OT" /* F5/ansi */
.byte 0x40 /* F6 */
.asciz "[17~" /* F6/screen/vt220/xterm/vt400 */
.byte 0x40 /* F6 */
.asciz "OU" /* F6/ansi */
.byte 0x41 /* F7 */
.asciz "[18~" /* F7/screen/vt220/xterm/vt400 */
.byte 0x41 /* F7 */
.asciz "OV" /* F7/ansi */
.byte 0x42 /* F8 */
.asciz "[19~" /* F8/screen/vt220/xterm/vt400 */
.byte 0x42 /* F8 */
.asciz "OW" /* F8/ansi */
.byte 0x43 /* F9 */
.asciz "[20~" /* F9/screen/vt220/xterm/vt400 */
.byte 0x43 /* F9 */
.asciz "OX" /* F9/ansi */
.byte 0x44 /* F10 */
.asciz "[21~" /* F10/screen/vt220/xterm/vt400 */
.byte 0x44 /* F10 */
.asciz "OY" /* F10/ansi */
.byte 0x85 /* F11 */
.asciz "[23~" /* F11/screen/xterm/vt400 */
.byte 0x85 /* F11 */
.asciz "OZ" /* F11/ansi */
.byte 0x86 /* F12 */
.asciz "[24~" /* F12/screen/xterm/vt400 */
.byte 0x52 /* Insert */
.asciz "[2~" /* Insert/screen/vt102/xterm */
.byte 0x53 /* Delete */
.asciz "[3~" /* Delete/screen/vt102/xterm */
.byte 0x4b /* Left */
.asciz "OD" /* Left/screen/vt102 */
.byte 0x4b /* Left */
.asciz "[D" /* Left/xterm */
.byte 0x47 /* Home */
.asciz "[1~" /* Home/screen/vt102 */
.byte 0x47 /* Home */
.asciz "[H" /* Home/xterm */
.byte 0x4f /* End */
.asciz "[4~" /* End/screen/vt102 */
.byte 0x4f /* End */
.asciz "[F" /* End/xterm */
.byte 0x48 /* Up */
.asciz "OA" /* Up/screen/vt102 app */
.byte 0x48 /* Up */
.asciz "[A" /* Up/xterm/vt102 ansi */
.byte 0x50 /* Down */
.asciz "OB" /* Down/screen/vt102 app */
.byte 0x50 /* Down */
.asciz "[B" /* Down/xterm/vt102 ansi */
.byte 0x49 /* PageUp */
.asciz "[5~" /* PageUp/screen/vt102/xterm */
.byte 0x51 /* PageDown */
.asciz "[6~" /* PageDown/screen/vt102/xterm */
.byte 0x4d /* Right */
.asciz "OC" /* Right/screen/vt102 app */
.byte 0x4d /* Right */
.asciz "[C" /* Right/xterm/vt102 ansi */
.byte 0 /* end of table marker */
/* init_serial_port
*
* Initialize serial port to 115200,8n1
* Serial interrupts disabled
*
* All registers except flags preserved
*/
init_serial_port:
pushw %ax
pushw %dx
pushw %bx
movw %cs:serial_port_base_address, %dx
addw $IER_OFFSET, %dx
xorb %al, %al
outb %al, %dx /* disable all serial interrupts */
addw $(LCR_OFFSET - IER_OFFSET), %dx /* LCR */
movb $(LCR_VALUE|LCR_DLAB), %al
outb %al, %dx /* enable divisor access */
movw %cs:serial_port_base_address, %dx
movw $(PORT_DIVISOR/PORT_SPEED), %bx
movb %bl, %al /* al = lsb of divisor */
outb %al, %dx /* set divisor latch lsb */
movb %bh, %al /* al = msb of divisor */
incw %dx
outb %al, %dx /* set divisor latch msb */
movw %cs:serial_port_base_address, %dx
addw $LCR_OFFSET, %dx
movb $LCR_VALUE, %al
outb %al, %dx /* disable divisor access */
addw $(MCR_OFFSET - LCR_OFFSET), %dx /* MCR */
movb $MCR_DTRRTS, %al
outb %al, %dx /* enable DTR + RTS */
movw %cs:serial_port_base_address, %dx
addw $FCR_OFFSET, %dx
movb $FCR_FIFO_ENABLE, %al
outb %al, %dx /* enable FIFOs */
popw %bx
popw %dx
popw %ax
ret
/* get_serial_lsr
*
* return serial line status register in %al
* return offset to serial port line status register io port in %dx
* all other registers except flags unchanged
*
* if status == 0xff return ZF=1, else return ZF=0
*/
get_serial_lsr:
movw %cs:serial_port_base_address, %dx
addw $LSR_OFFSET, %dx
inb %dx, %al
cmpb $0xff, %al
ret
/*
* get_byte
*
* get serial byte in %al, scancode in %ah [FIXME: EFI console input]
*
* all registers except %ax preserved
*
*/
get_byte:
pushw %dx
pushw %bx
next_serial_char:
call get_serial_lsr /* get serial lsr in %al */
jz get_byte_tail /* no port present... */
testb $1, %al /* bit 0 of LSR = 1 = data available */
jz get_byte_tail /* no input waiting */
/* new character found on serial port */
/* convert it to a scancode */
movw %cs:serial_port_base_address, %dx
inb %dx, %al /* al = serial input char */
testb $0x80, %al /* non-ascii char received? */
jnz next_serial_char /* throw char away */
movb %al, %dl /* dl = character read */
pushw %ds
pushw %cs
popw %ds /* ds = cs */
movw $ascii2scan, %bx /* table to translate ascii->scan */
xlatb /* translate char to scancode */
popw %ds
/* shift status is ignored at this point, may be used later */
andb $0x7f, %al /* strip shift status from table */
movb %al, %ah /* scancode goes in high byte */
movb %dl, %al /* "translated" ascii in lower byte */
cmpb $0x7f, %al /* Did the user transmit ascii DEL? */
jnz get_byte_not_del /* if not, don't do anything to al */
movb $0x08, %al /* else delete becomes backspace */
get_byte_not_del:
testw %ax, %ax /* clear zero flag */
get_byte_tail:
popw %bx
popw %dx
ret
/*
* poll_byte
*
* get serial byte in %al, scancode in %ah [FIXME: EFI console input]
* retry up to 65536 times for an expected input byte
*
* all registers except %ax preserved
*
*/
poll_byte:
pushw %cx
xorw %cx, %cx
poll_byte_retry:
inb $0xed, %al
call get_byte
loopz poll_byte_retry /* repeat while zf set or cx != 0 */
popw %cx
ret
/*
* get_multibyte
*
* after an escape character, poll for terminal keys that generate
* an escape code plus multiple bytes (up to four).
*
* if no byte is waiting, all registers preserved except flags
* if more bytes are waiting, all registers preserved except %ax and flags
*
*/
get_multibyte:
pushw %bp /* bp points to temp buffer on stack */
pushw %bx /* bx points to multibyteinput table */
pushw %cx /* cx will count chars */
pushw %ax /* ax will receive chars */
pushl $0 /* make space on stack for 4 chars */
xorw %cx, %cx /* cx = 0 */
movw %sp, %bp /* point bp at temp data */
call poll_byte /* is a character waiting? */
jz get_multibyte_tail /* if not, bail */
get_multibyte_store:
movb %al, (%bp) /* store char received */
incb %cl /* mark one char received */
incw %bp /* point to next char */
cmpb $4, %cl /* got enough chars? */
jz got_multibyte /* no strings longer than 4 chars */
call poll_byte /* is another char waiting? */
jnz get_multibyte_store /* store a new one if it's there */
got_multibyte:
movw $multibyteinput, %bx /* point to first scancode */
got_multibyte_findkey:
movw %sp, %bp /* bp = start of buffer */
movb %cs:(%bx), %ah /* ah = scancode */
incw %bx /* bx = start of test string */
orb %ah, %ah /* is it zero? */
jz get_multibyte_tail /* if so, bail, key not found */
got_multibyte_nextchar:
movb %cs:(%bx), %ch /* ch = test char to compare */
incw %bx /* point to next char */
orb %ch, %ch /* is char to compare NUL? */
jz got_multibyte_key /* matched to end of a string! */
cmpb %ch, (%bp) /* input tmp buf equal to test char? */
jnz got_multibyte_try_next_key
/* note: expected that test string will be nul before input string */
/* no attempt is made to ensure no more than 4 bytes stack read */
incw %bp /* point to next input */
jmp got_multibyte_nextchar
got_multibyte_try_next_key: /* align to next scancode/ascii pair */
movb %cs:(%bx), %ch /* ch = test char to compare */
incw %bx /* point to next char */
orb %ch, %ch /* is char to compare NUL? */
jnz got_multibyte_try_next_key
jmp got_multibyte_findkey
got_multibyte_key:
xorb %al, %al /* ascii value = 0 for special keys */
movw %sp, %bp
movw %ax, 4(%bp) /* overwrite old %ax value with key */
get_multibyte_tail:
addw $4, %sp /* pop temp space */
popw %ax
popw %cx
popw %bx
popw %bp
ret
/*
* send_byte
*
* send character in %al to serial port [FIXME: EFI console out]
*
* all registers preserved except flags
*
*/
send_byte:
pushw %ax
pushw %dx
pushw %cx
testb $0x80, %al /* don't send non-ascii chars */
jnz send_tail /* these should be translated earlier */
movb %al, %ah /* save char to output in %ah */
movw $0xFFF0, %cx /* only retry 65520 times */
serial_ready_test:
call get_serial_lsr /* get serial lsr in %al */
testb $TRANSMIT_READY_BIT, %al
loopz serial_ready_test /* if !tx ready, loop while cx!=0 */
movb %ah, %al
movw %cs:serial_port_base_address, %dx
outb %al, %dx
send_tail:
popw %cx
popw %dx
popw %ax
ret
/*
* translate_char
*
* translate vga character in %al to ascii
*
* returns:
* al = translated character
*
* all registers except %al preserved
*
*/
translate_char:
pushw %bx
pushw %ds
pushw %cs
popw %ds /* ds = cs */
testb $0x80, %al
jz translate_char_ctrl
andb $0x7f, %al
movw $high2ascii, %bx
xlatb
translate_char_ctrl:
cmpb $0x20, %al
jnc translate_char_tail
movw $ctrl2ascii, %bx
xlatb
translate_char_tail:
popw %ds
popw %bx
ret
/*
* translate_char_tty
*
* translate vga character in %al to ascii
* unless %al == 7, 8, 10, or 13 (bell, bs, lf, cr)
*
* returns:
* al = translated character
*
* all registers except %al preserved
*
*/
translate_char_tty:
cmpb $0x07, %al /* bell */
jz translate_char_tty_tail
cmpb $0x08, %al /* backspace */
jz translate_char_tty_tail
cmpb $0x0a, %al /* LF */
jz translate_char_tty_tail
cmpb $0x0d, %al /* CR */
jz translate_char_tty_tail
call translate_char
translate_char_tty_tail:
ret
/*
* send_char
*
* send character 0 - 255 in %al out through serial port
* increment cursor position without control processing
*
* send_byte is used for data that isn't tracked
*
* send_char is used for text that should be tracked
* send_char outputs all characters as non-control chars
*
* returns:
* al = translated character
*
* all registers except %al preserved
*
*/
send_char:
call sgabioslog_save_char /* save original char+pos */
call translate_char
jmp send_char_tty_out
/* after ctrl translation, same as send_char_tty */
/*
* send_char_tty
*
* send character 0 - 255 in %al out through serial port
* increment cursor position *with* control processing
* for bell, linefeed, cr, and backspace (others all printable)
*
* send_byte is used for data that isn't tracked
*
* send_char_tty is used for text that should be tracked
*
* returns:
* al = translated character
*
* all registers except %al preserved
*
*/
/* send character 0 - 255 in %al out through serial port */
/* increment cursor position with CR/LF/Backspace processing */
send_char_tty:
call sgabioslog_save_char /* save original char+pos */
call translate_char_tty
send_char_tty_out:
pushw %dx
call update_serial_cursor
call get_current_cursor /* vga cursor in %dx */
cmpb $0x0d, %al /* CR */
jnz send_char_tty_nul /* if not CR, check for NUL */
orb %dl, %dl /* already at col 0? */
jz send_char_tty_tail /* no need to re-send CR */
send_char_tty_nul:
orb %al, %al /* %al == 0 ? (nul) */
/* more than likely, we have NUL at this point because the caller */
/* tried to read a char using int $0x10, %ah=8, and is trying */
/* to re-output it with different attributes - for now send nothing */
jz send_char_tty_tail
send_char_tty_write:
call memconsole_log_char /* log character sent */
call send_byte
cmpb $0x07, %al /* bell */
jz send_char_tty_tail /* no cursor update for bell */
cmpb $0x08, %al /* backspace */
jz send_char_tty_backspace
cmpb $0x0a, %al /* LF */
jz send_char_tty_lf
cmpb $0x0d, %al /* CR */
jz send_char_tty_cr
incb %dl
jmp send_char_tty_tail
send_char_tty_backspace:
orb %dl, %dl
jz send_char_tty_tail
decb %dl
jmp send_char_tty_tail
send_char_tty_lf:
incb %dh
jmp send_char_tty_tail
send_char_tty_cr:
xorb %dl, %dl
send_char_tty_tail:
cmpb %cs:term_cols, %dl
jc send_char_tty_check_rows
movb %cs:term_cols, %dl
decb %dl /* dl = cols - 1 */
send_char_tty_check_rows:
cmpb %cs:term_rows, %dh
jc send_char_tty_save_cursor
movb %cs:term_rows, %dh
decb %dh /* dh = rows - 1 */
send_char_tty_save_cursor:
call set_current_cursor
pushw %ds
pushw $BDA_SEG
popw %ds
/* save current position as the serial terminal position */
/* since a character was just output at that position */
movw %dx, BDA_SERIAL_POS
popw %ds
popw %dx
ret
/*
* send_asciz_out
*
* send nul terminated string pointed to by %ds:%si
* to serial port without text tracking
*
* indended to be used for multi-byte send_byte
*
* all registers preserved except flags
*/
send_asciz_out:
pushw %ax
pushw %si
cld
send_asciz_loop:
lodsb
test %al,%al
jz send_asciz_end
call send_byte
jmp send_asciz_loop
send_asciz_end:
popw %si
popw %ax
ret
/*
* send_string
*
* send cx chars in string pointed to by %ds:%si
* to serial port with tty tracking
*
* indended to be used for multi-byte send_char_tty
*
* all registers preserved except flags
*/
send_string:
pushw %ax
pushw %si
cld
send_string_loop:
lodsb
call send_char_tty
loop send_string_loop
popw %si
popw %ax
ret
/*
* send_string
*
* send cx chars in string pointed to by %ds:%si
* with interleaved attribute data
*
* indended to be used for multi-byte send_char_tty
* with interleaved vga attribute updates
*
* all registers preserved except flags
*/
send_attr_string:
pushw %ax
pushw %bx
pushw %si
cld
send_attr_string_loop:
lodsb
call send_char_tty
lodsb
movb %al, %bl
call send_attribute /* send attribute in %bl */
loop send_attr_string_loop
popw %si
popw %bx
popw %ax
ret
/*
* send_number
*
* send ascii version of number in %al to serial port
*
* intended for ansi cursor positions and attributes,
* so cursor position is not tracked/updated
*
* all registers preserved except flags
*/
send_number:
pushw %ax
pushw %bx
aam /* ah = al/10, al = al mod 10 */
movw %ax, %bx /* bh = al/10, bl = al mod 10 */
movb %bh, %al
aam /* ah = bh/10, al = bh mod 10 */
movb %al, %bh /* bh = 10s digit, bl = 1s digit */
movb %ah, %al /* ah = al = 100s digit */
testb %al, %al /* is there a 100s digit? */
jz send_tens /* move to tens if not */
orb $0x30, %al /* al = ascii value of digit */
call send_byte
send_tens:
orb %bh, %ah /* bh = 10s, ah = 100s digits */
jz send_ones /* non-zero = must send tens */
movb %bh, %al /* al = bh = 10s digit */
orb $0x30, %al /* al = ascii value of digit */
call send_byte
send_ones:
movb %bl, %al /* al = bl = 1s digit */
orb $0x30, %al /* al = ascii value of digit */
call send_byte
popw %bx
popw %ax
ret
/*
* send_crlf
*
* send CRLF to serial port
*
* FIXME: used at vga init and for scrolling terminal
* so position is not tracked. Callers of this routine
* predate the code that does smart tty/cursor output.
*
* Callers should probably be changed to use those
* routines or send_crlf changed to use them and
* terminal scrolling fixed to use linefeed only.
*
* all registers preserved except flags
*/
send_crlf:
pushw %ax
movb $0x0d, %al
call send_byte
movb $0x0a, %al
call send_byte
popw %ax
ret
/*
* send_ansi_csi
*
* send ESCAPE [ to serial port
*
* output is not tracked since these are control sequences
*
* all registers preserved except flags
*/
send_ansi_csi: /* transmit ESC [ */
pushw %ax
movb $0x1b, %al /* escape */
call send_byte
movb $0x5b, %al /* [ */
call send_byte
popw %ax
ret
/*
* send_ansi_csi_2num
*
* send ESC [ %dh ; %dl to serial port
*
* since both position and attribute updates generally have
* two parameters, this function converts values in dx to
* two ascii numbers. It's expected that the caller will
* output the final trailing H or m or whatever is required.
*
* output is not tracked since these are control sequences
*
* all registers preserved except flags
*/
send_ansi_csi_2num:
/* send ESC [ %dh ; %dl */
pushw %ax
call send_ansi_csi /* esc [ */
movb %dh, %al
call send_number
movb $0x3b, %al /* semicolon */
call send_byte
movb %dl, %al
call send_number
popw %ax
ret
/*
* send_ansi_cursor_pos
*
* send ESC [ %dh+1 ; %dl+1 to serial port to position
* cursor
*
* since both position and attribute updates generally have
* two parameters, this function converts values in dx to
* two ascii numbers, after adding 1 to both dh and dl.
*
* output is not tracked since this is a control sequence
*
* all registers preserved except flags
*/
send_ansi_cursor_pos:
pushw %ax
pushw %dx
addw $0x0101, %dx /* dh += 1, dl += 1 */
call send_ansi_csi_2num /* send esc [ %dh+1;%dl+1 */
movb $0x48, %al /* H */
call send_byte
popw %dx
popw %ax
ret
/*
* send_attribute
*
* send ansi attribute change ESC [ 4x ; 3y ; (1|22)m
* if the attribute has changed since last sent (stored in bda)
*
* output is not tracked since this is a control sequence
*
* all registers preserved except flags
*/
send_attribute:
andb $0x7f, %bl /* ansi has no bright bg */
pushw %ds
pushw %es
pushw %ax
pushw %bx
pushw %dx
pushw $BDA_SEG
popw %es /* es = 0x40 */
pushw %cs
popw %ds /* ds = cs */
cmpb %es:BDA_COLOR_VAL, %bl
jz send_attribute_tail
cmpb $0x07, %bl /* is it white on black? */
jnz send_attribute_color
/* for white on black, send esc [ m */
call send_ansi_csi
jmp send_attribute_m /* send the m, return */
send_attribute_color:
movb %bl, %ah /* ah = attribute */
movw $colortable, %bx
movb %ah, %al
andb $7, %al /* al = fg attr */
xlatb /* al = fg ansi num */
movb %al, %dl /* dl = fg ansi num */
movb %ah, %al
shrb $4, %al /* al = bg attr */
xlatb /* al = bg ansi num */
movb %al, %dh /* dh = bg ansi num */
addw $0x281e, %dx /* 3x=setfg, 4x=setbg */
call send_ansi_csi_2num
movb $0x3b, %al /* semicolon */
call send_byte
shlb $4, %ah /* bright text? */
sets %al /* if bit 7, al = 1 */
js send_attribute_intensity
movb $22, %al /* 22 = normal intensity */
send_attribute_intensity:
call send_number /* either 22 or 1 */
send_attribute_m:
movb $0x6d, %al /* m */
call send_byte
send_attribute_tail:
popw %dx
popw %bx
/* mark attribute in %bl the current one */
movb %bl, %es:BDA_COLOR_VAL
popw %ax
popw %es
popw %ds
ret
/*
* serial_get_input
*
* common code for both interrupt-driven and non-interrupt
* driven serial input. Called only when LSR bit 1 is set.
*
* No parameters, no return values
*
* Preserves all registers
*/
serial_get_input:
pushf
/* be paranoid about int 9h happening during update */
cli
pushaw
pushw %ds
/* next char input buffer is at 0x40:0x1c */
pushw $BDA_SEG
popw %ds /* es = 0x40 */
call get_byte /* next scancode/byte in %ax */
cmpb $0x1b, %al /* look for escape */
jnz serial_gotkey /* not escape, don't look for more bytes */
call get_multibyte /* look for any chars after escape */
serial_gotkey:
movw KBD_TAIL, %bx /* bx = keyboard tail pointer */
movw %ax, (%bx) /* store key in buffer */
addw $2, %bx /* point to next location */
cmpw $KBD_BUF_END, %bx /* did the buffer wrap? */
jb kbd_buf_no_wrap
movw $KBD_BUF_START, %bx
kbd_buf_no_wrap:
movw %bx, KBD_TAIL /* update tail pointer to show key */
popw %ds
popaw
popf
ret
/*
* irq3_isr
*
* entry point for irq 3 / int 0x0b / exception 11
*
* Called when COM2 or COM4 have characters pending
*
* The segment not present exception should never happen
* in real mode 16-bit code like this, but just to be safe,
* if this interrupt is invoked and no characters are
* pending on the port found in serial_port_base_address,
* this routine will chain to the original handler.
*
* If characters are found pending, they will be processed
* and control returned via iret.
*/
irq3_isr:
#if 0
pushw %ax
pushw %dx
/* placeholder, this shouldn't ever happen */
/* no interrupts are configured outside COM1 */
call get_serial_lsr /* get serial lsr in %al */
jz chain_irq3 /* no port present... */
testb $1, %al /* bit 0 of LSR = 1 = data available */
jz chain_irq3 /* no input waiting */
call serial_get_input /* get input and stuff kbd buffer */
movb $0x20, %al
outb %al, $0x20 /* send non-specific EOI */
popw %dx
popw %ax
iret
chain_irq3:
popw %dx
popw %ax
#endif
jmp do_old_irq3
/*
* irq4_isr
*
* entry point for irq 4 / int 0x0c / exception 12
*
* Called when COM1 or COM3 have characters pending
*
* The stack fault exception may occur if code attempts to
* read from sp:0xffff, so if this interrupt is invoked and
* no characters are pending on the port found in
* serial_port_base_address, this routine will chain to the
* original handler.
*
* If characters are found pending, they will be processed
* and control returned via iret.
*/
irq4_isr:
#if 0
pushw %ax
pushw %dx
call get_serial_lsr /* get serial lsr in %al */
jz chain_irq4 /* no port present... */
testb $1, %al /* bit 0 of LSR = 1 = data available */
jz chain_irq4 /* no input waiting */
call serial_get_input /* get input and stuff kbd buffer */
movb $0x20, %al
outb %al, $0x20 /* send non-specific EOI */
popw %dx
popw %ax
iret
chain_irq4:
popw %dx
popw %ax
#endif
jmp do_old_irq4
/*
* int14h_isr
*
* entry point for int 14h
*
*/
int14h_isr:
pushaw
movw %sp, %bp
addw $16, %bp /* bp points to return address */
orb %ah, %ah /* fn 0x00, initialize port */
jz int14h_init_port
cmpb $0x04, %ah /* fn 0x04, extended intialize */
jnz chain_isr14h
int14h_init_port:
/* check for init port = current port */
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movw %dx, %bx /* bx = port number */
shlw $1, %bx /* bx = port number * 2 */
andw $7, %bx /* bx = bda offset of serial io addr */
movw (%bx), %cx /* cx = io address of port to init */
popw %ds /* restore original ds */
cmpw %cx, %cs:serial_port_base_address
jnz chain_isr14h /* if different, don't get in the way */
/* init port == current port */
pushw %ds
/* LILO 22.6 HACK STARTS HERE */
movw (%bp), %bx /* return address for int 14h call */
movw 2(%bp), %ds /* return segment for int 14h call */
cmpl $0x4f4c494c, 0x06 /* does segment have lilo signature? */
jnz int14h_init_tail /* not lilo, bail on hack */
cmpw $0x0616, 0x0a /* does version match lilo 22.6? */
jnz int14h_init_tail /* unknown lilo release, bail on hack */
movb $0, 0x12 /* set lilo com port = 0 */
movl $0x90c3585a, (%bx) /* return code= pop dx;pop ax;ret;nop */
/* now lilo 22.6's own serial out is permanently disabled */
/* this prevents double-character output from int10h + serial */
/* this also prevents lilo from stealing serial input chars */
/* END LILO 22.6 HACK */
int14h_init_tail:
popw %ds
popaw
pushw %dx /* get_serial_lsr trashes %dx */
call get_serial_lsr /* return serial status in %al */
xorb %ah, %ah /* return serial status in %ax */
popw %dx /* restore %dx */
iret
chain_isr14h:
popaw
jmp do_old_int14h
/*
* int16h_isr
*
* entry point for int 16h
*
* keyboard characters are usually retrieved by calling
* int 16h, generally placed in the keyboard buffer by
* irq 1 (int 9h). Poll serial port for new data before
* chaining to int 16h to fake irq 1 behavior
*
* all registers preserved except flags (later iret will restore)
* bda updated with a new keypress if available
*
* FIXME: handle multi-byte keypresses like cursor up/down
* to send proper scancodes for navigating lilo menus
*/
int16h_isr:
pushw %ax
pushw %dx
/* each time int 16h is invoked, fake an int 9h */
/* except read the serial input buffer */
/* then chain to the original int 16h for processing */
call get_serial_lsr
jz chain_isr16h /* no port present... */
testb $1, %al /* bit 0 of LSR = 1 = data available */
jz chain_isr16h /* no input waiting */
call serial_get_input /* get input and stuff kbd buffer */
/* for now, leave remaining chars pending in serial fifo */
/* int 16h callers only get one char at a time anyway */
chain_isr16h:
popw %dx
popw %ax
jmp do_old_int16h
/*
* update serial_cursor
*
* figure out where the cursor was, and where it's going
* use the minimal amount of serial output to get it there
* input: vga cursor and serial cursor positions stored in BDA
*
* all registers preserved except flags
* bda updated with new position for serial console cursor
*/
update_serial_cursor:
pushw %ax
pushw %bx
pushw %dx
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
call get_current_cursor /* dh = row, dl = col */
movw BDA_SERIAL_POS, %bx /* bh = row, bl = col */
subb %dl, %bl /* -col update */
negb %bl /* col update */
subb %dh, %bh /* -row update */
negb %bh /* row update */
/* handle a few special movement cases */
/* cr, lf, bs, bs+bs, space, else send full ansi position */
orb %dl, %dl /* column zero? */
jnz update_serial_cursor_lf
movb $0x0d, %al /* CR */
call send_byte
xorb %bl, %bl /* mark no diff in col */
update_serial_cursor_lf:
cmpb $1, %bh /* +1 row? */
jnz update_serial_cursor_bs
movb $0x0a, %al /* LF */
call send_byte
xorb %bh, %bh /* mark no diff in row */
update_serial_cursor_bs:
cmpb $-1, %bl /* one char back */
jz update_serial_cursor_one_bs
cmpb $-2, %bl /* two chars back */
jnz update_serial_cursor_space /* check for space */
movb $0x08, %al /* BS */
call send_byte
update_serial_cursor_one_bs:
movb $0x08, %al /* BS */
call send_byte
xorb %bl, %bl /* mark no diff in col */
update_serial_cursor_space:
cmpb $1, %bl /* one char forward */
jnz update_serial_cursor_up
movb $0x20, %al /* space */
call send_byte
xorb %bl, %bl /* mark no diff in col */
update_serial_cursor_up:
cmpb $-1, %bh /* -1 row? */
jnz update_serial_cursor_full /* do full ansi pos update */
call send_ansi_csi /* send ESC [ A (cursor up) */
movb $0x41, %al /* A */
call send_byte
xorb %bh, %bh /* mark no diff in row */
update_serial_cursor_full:
orw %bx, %bx /* diff = 0? */
jz update_serial_cursor_done
call send_ansi_cursor_pos /* set cursor pos from dh,dl */
update_serial_cursor_done:
movw %dx, BDA_SERIAL_POS
popw %ds
popw %dx
popw %bx
popw %ax
ret
/*
* write_teletype
*
* handle int 10h, function 0eh
*
* ah = 0x0e write teletype character
* al = character ascii code
* bh = display page number
*
* all registers except %al preserved
* caller will restore all registers
*/
write_teletype:
pushw %bx
movb $0x07, %bl /* black bg, white fg */
call send_attribute
popw %bx
call send_char_tty
ret
/*
* write_attr_char
*
* handle int 10h, function 09h
*
* ah = 0x09 write attribute/character at current cursor position
* al = character ascii code
* bh = display page number
* bl = character attribute
* cx = repetition count
*
* does not update cursor position
* all registers except %cx and %al preserved
* caller will restore all registers
*/
write_attr_char:
call send_attribute /* send attribute in %bl */
jmp write_char_common
/*
* write_char
*
* handle int 10h, function 0ah
*
* ah = 0x0a write character at current cursor position
* al = character ascii code
* bh = display page number
* cx = repetition count
*
* does not update cursor position
* all registers except %cx and %al preserved
* caller will restore all registers
*/
write_char:
pushw %bx
movb $0x07, %bl /* black bg, white fg */
call send_attribute
popw %bx
write_char_common:
call get_current_cursor
call send_char
/* make cx=0 and cx=1 only output one char */
cmpw $1, %cx
jbe write_char_tail
decw %cx
jmp write_char
write_char_tail:
/* put cursor back where it was on entry */
call set_current_cursor
ret
/*
* write_string
*
* handle int 10h, function 13h
*
* ah = 0x13 write character at current cursor position
* al = 0, data = char, ..., no cursor update
* al = 1, data = char, ..., cursor at end of string
* al = 2, data = char+attr, ..., no cursor update
* al = 3, data = char+attr, ..., cursor at end of string
* bh = display page number
* bl = character attribute for all chars (if al = 0 or 1)
* cx = characters in string (attributes don't count)
* dh = cursor row start
* dl = cursor column start
* es:bp = pointer to source text string in memory
*
* all registers preserved except flags
* caller will restore all registers
*/
write_string:
call set_cursor_position
pushw %ds
pushw %es
pushw %es
popw %ds /* ds = es */
movw %bp, %si /* si = bp */
testb $2, %al
jnz write_attr_string
call send_attribute /* send attribute in %bl */
test %cx, %cx
jz write_string_empty
call send_string /* plaintext out */
write_string_empty:
jmp write_string_update_cursor
write_attr_string:
call send_attr_string /* text+attrib out */
write_string_update_cursor:
testb $1, %al /* cursor update? */
jnz write_string_tail /* yes? already happened */
/* restore entry cursor position if no update */
call set_cursor_position
write_string_tail:
popw %es
popw %ds
ret
/*
* set_cursor_position
*
* handle int 10h, function 02h
*
* ah = 0x02 set cursor position
* bh = display page number
* dh = cursor row
* dl = cursor column
*
* update bda cursor position with value in %dx
* serial console cursor only updated on text output
* this routine also called by set_current_cursor
* which won't bother setting ah = 2
*
* all registers preserved except flags
*/
set_cursor_position:
pushw %ax
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movzbw %bh, %ax /* ax = page number */
andb $0x07, %al /* prevent invalid page number */
shlb $1, %al /* calculate word offset */
addb $BDA_CURSOR_BUF, %al /* ax = cursor save offset */
movw %ax, %bx /* bx = cursor save offset */
movw %dx, (%bx) /* save new cursor value */
popw %ds
popw %ax
ret
/*
* set_current_cursor
*
* get current display page number and call set_cursor_positon
* to store the row/column value in dx to the bda
*
* all registers preserved except flags
*/
set_current_cursor:
pushw %ds
pushw %bx
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movb BDA_ACTIVE_PAGE, %bh
call set_cursor_position
popw %bx
popw %ds
ret
/*
* get_cursor_common
*
* read cursor position for page %bh from bda into %dx
*
* returns:
* dh = cursor row
* dl = cursor column
* ch = cursor start scanline
* cl = cursor end scanline
*
* all registers except %dx, %cx preserved
*/
get_cursor_common:
pushw %bx
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movzbw %bh, %bx /* dx = current page */
andb $7, %bl
shlb $1, %bl
addb $BDA_CURSOR_BUF, %bl
movw (%bx), %dx /* get cursor pos */
movw BDA_CURSOR_SCAN, %cx
popw %ds
popw %bx
ret
/*
* get_current_cursor
*
* read cursor position for current page from bda into %dx
*
* returns:
* dh = cursor row
* dl = cursor column
*
* all registers except %dx preserved
*/
get_current_cursor:
pushw %ds
pushw %bx
pushw %cx
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movb BDA_ACTIVE_PAGE, %bh
call get_cursor_common
popw %cx
popw %bx
popw %ds
ret
/*
* get_cursor_position
*
* handle int 10h, function 03h
*
* ah = 0x02 get cursor position
* bh = display page number
*
* returns:
* ax = 0
* ch = cursor start scanline
* ch = cursor end scanline
* dh = cursor row
* dl = cursor column
*
* all registers except %ax, %cx, %dx preserved
*/
get_cursor_position:
call bail_if_vga_attached /* does not return if vga attached */
popw %ax /* not chaining, pop fake return address */
popw %dx /* not chaining, pop saved cursor position */
popaw /* not chaining to old int 10h, pop saved state */
call get_cursor_common
xorw %ax, %ax
iret
/*
* return_current_video_state
*
* handle int 10h, function 0fh
*
* ah = 0x0f return current video state
*
* returns:
* ah = number of columns on screen (from 40:4a)
* al = current video mode setting (from 40:49)
* bh = active display page number (from 40:62)
*
* all registers except %ax and %bh preserved
*/
read_current_video_state:
call bail_if_vga_attached /* does not return if vga attached */
popw %ax /* not chaining, pop fake return address */
popw %dx /* not chaining, pop saved cursor position */
popaw /* not chaining to old int 10h, pop saved state */
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movb BDA_COLS, %ah
movb BDA_MODE_NUM, %al
movb BDA_ACTIVE_PAGE, %bh
popw %ds
iret
/*
* read_attr_char
*
* handle int 10h, function 08h
*
* ah = 0x08 read character/attribute from screen
*
* returns:
* ah = attribute at current cursor position
* al = character read from current cursor position
*
* all registers preserved except %ax and flags
*/
read_attr_char:
call bail_if_vga_attached /* does not return if vga attached */
popw %ax /* not chaining, pop fake return address */
popw %dx /* not chaining, pop saved cursor position */
popaw /* not chaining to old int 10h, pop saved state */
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movb BDA_COLOR_VAL, %ah /* return last color value */
call sgabioslog_get_char
popw %ds
iret
/*
* set_video_mode
*
* handle int 10h, function 00h
*
* ah = 0x00 set video mode
* al = video mode
*
* unless bit 7 of al = 1, setting mode clears screen
*
* all registers preserved except %bh, %dx, flags
*/
set_video_mode:
testb $0x80, %al /* preserve screen flag? */
jnz set_video_mode_tail
call send_ansi_csi
movb $0x32, %al /* 2 */
call send_byte
movb $0x4a, %al /* J */
call send_byte
set_video_mode_tail:
movb $0x07, %bl /* white on black text */
call send_attribute /* send attribute in %bl */
/* set cursor position to 0,0 */
xorb %bh, %bh /* page 0 */
xorw %dx, %dx
jmp set_cursor_position
/*
* scroll_page_up
*
* handle int 10h, function 06h
*
* ah = 0x06 scroll current page up
* al = scroll distance in character rows (0 blanks entire area)
* bh = attribute to used on blanked lines
* ch = top row (upper left corner) of window
* cl = left-most column (upper left corner) of window
* dh = bottom row (lower right corner) of window
* dl = right-most column (lower right corner) of window
*
* all registers preserved except flags
*/
scroll_page_up:
pushw %si
pushw %dx
call get_current_cursor /* save current cursor */
movw %dx, %si /* si = vga cursor pos */
popw %dx
cmpb $0, %al /* al = 0 = clear window */
jz scroll_common_clear
pushw %ax
call send_ansi_csi /* CSI [ %al S */
call send_number
movb $0x53, %al /* S */
call send_byte
popw %dx
popw %si
ret
/*
* scroll_common_clear
*
* common tail for up/down scrolls to clear window specified
* in %cx and %dx.
*
* stack should contain saved copy of si
* si = original vga cursor position on service entry
*
* bh = attribute to used on blanked lines
* ch = top row (upper left corner) of window
* cl = left-most column (upper left corner) of window
* dh = bottom row (lower right corner) of window
* dl = right-most column (lower right corner) of window
*/
scroll_common_clear:
pushw %ax
xchgb %bl, %bh /* bl = attribute, bh = old bl */
call send_attribute /* send attribute in %bl */
xchgb %bl, %bh /* restore bx */
pushw %ds
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
/* check to see if region is full screen, and attribute default */
orw %cx, %cx /* is top left 0,0? */
jnz scroll_common_window /* no, handle window */
cmpb $0x07, %bh /* is attribute white on black? */
jnz scroll_common_window /* no, must write spaces */
#ifdef LILO_CLEAR_WORKAROUND_NOT_REQUIRED
cmpb %cs:term_cols, %dl /* is right less than cols ? */
jc scroll_common_window /* if so, handle window */
cmpb %cs:term_rows, %dh /* is bottom less than rows ? */
jc scroll_common_window /* if so, handle window */
#endif
/* safe to send standard clear screen sequence */
call send_ansi_csi /* send ESC [ */
movb $0x32, %al /* 2 */
call send_byte
movb $0x4a, %al /* J */
call send_byte
jmp scroll_common_tail
scroll_common_window:
pushw %dx
movw %cx, %dx /* dx = upper right */
call set_current_cursor
popw %dx
pushw %cx
/* setup cx with count of chars to clear per row */
xorb %ch, %ch
negb %cl
addb %dl, %cl /* cl = dl - cl */
incb %cl /* start = end col = clear 1 col */
cmpb %cs:term_cols, %cl /* is count < cols? */
jc scroll_common_row_ok /* if so then skip limit */
movb %cs:term_cols, %cl /* limit count to cols */
scroll_common_row_ok:
jz scroll_common_row_done /* count == 0 ? */
movb $0x20, %al /* space */
scroll_common_space_loop:
call send_char
loop scroll_common_space_loop /* send cx spaces */
scroll_common_row_done:
popw %cx
incb %ch /* top left now next row */
cmpb %dh, %ch
jbe scroll_common_window /* do next row */
scroll_common_tail:
popw %ds
popw %ax
pushw %dx
movw %si, %dx /* dx = saved vga cursor pos */
call set_current_cursor /* restore saved cursor */
popw %dx
popw %si
ret
/*
* scroll_page_down
*
* handle int 10h, function 07h
*
* ah = 0x07 scroll current page down
* al = scroll distance in character rows (0 blanks entire area)
* bh = attribute to used on blanked lines
* ch = top row (upper left corner) of window
* cl = left-most column (upper left corner) of window
* dh = bottom row (lower right corner) of window
* dl = right-most column (lower right corner) of window
*
* FIXME: this routine doesn't handle windowing, it currently
* only handles one line screen scrolls and erasing entire screen
*
* all registers preserved except flags
*/
scroll_page_down:
pushw %si
pushw %dx
call get_current_cursor /* save current cursor */
movw %dx, %si /* si = vga cursor pos */
popw %dx
cmpb $0, %al /* al = 0 = clear window */
jz scroll_common_clear
pushw %ax
call send_ansi_csi /* CSI [ %al T */
call send_number
movb $0x54, %al /* T */
call send_byte
popw %dx
popw %si
ret
/*
* bail_if_vga_attached
*
* Check for vga installed, if not, return to caller.
* If so, pop return address, return to chain_isr_10h
*
* expected that routine calling this one has chain_isr_10h
* as the next item on the stack
*
* all registers except flags and sp preserved
*/
bail_if_vga_attached:
cmpw $0xc000, %cs:old_int10h_seg /* vga attached? */
jnz bail_tail /* if not, don't modify stack */
addw $2, %sp /* else drop first return address */
bail_tail:
ret /* return to caller or chain_isr_10h */
/*
* int10h_isr
*
* entry point for int 10h
*
* save all registers, force return to chain to previous int10h isr
* decide which function in ah needs to be dispatched
*
* ah = 0x00 set mode
* ah = 0x01 set cursor type
* ah = 0x02 set cursor position
* ah = 0x03 read cursor position
* ah = 0x04 read light pen position
* ah = 0x05 set active display page
* ah = 0x06 scroll active page up
* ah = 0x07 scroll active page down
* ah = 0x08 read attribute/character at cursor
* ah = 0x09 write attribute/character at cursor
* ah = 0x0a write character at cursor position
* ah = 0x0b set color palette
* ah = 0x0c write pixel
* ah = 0x0d read pixel
* ah = 0x0e write teletype
* ah = 0x0f read current video state
* ah = 0x10 set individual palette registers
* ah = 0x11 character generation (font control/info)
* ah = 0x12 alternate select (video control/info)
* ah = 0x13 write string
* ah = 0x1a read/write display combination code
* ah = 0x1b return functionality/state information
* ah = 0x1c save/restore video state
* ah = 0x4f vesa bios calls
* all registers preserved except flags (later iret will restore)
*/
int10h_isr:
pushaw
call get_current_cursor
pushw %dx /* save current cursor */
pushw %bp /* need bp for indexing off stack */
movw %sp, %bp /* bp = sp */
movw 14(%bp), %dx /* restore dx from earlier pushaw */
popw %bp /* restore old bp */
pushw $chain_isr10h /* force return to chain_isr10h */
testb %ah, %ah
jnz int10h_02
jmp set_video_mode
int10h_02:
cmpb $0x02, %ah
jnz int10h_03
jmp set_cursor_position
int10h_03:
cmpb $0x03, %ah
jnz int10h_06
jmp get_cursor_position
int10h_06:
cmpb $0x06, %ah
jnz int10h_07
jmp scroll_page_up
int10h_07:
cmpb $0x07, %ah
jnz int10h_08
jmp scroll_page_down
int10h_08:
cmpb $0x08, %ah
jnz int10h_09
jmp read_attr_char
int10h_09:
cmpb $0x09, %ah
jnz int10h_0a
jmp write_attr_char
int10h_0a:
cmpb $0x0a, %ah
jnz int10h_0e
jmp write_char
int10h_0e:
cmpb $0x0e, %ah
jnz int10h_0f
jmp write_teletype
int10h_0f:
cmpb $0x0f, %ah
jnz int10h_13
jmp read_current_video_state
int10h_13:
cmpb $0x13, %ah
jnz int10h_default
jmp write_string
int10h_default:
popw %ax /* pop chain_isr10h return address */
chain_isr10h:
popw %dx /* pop saved cursor */
cmpw $0xc000, %cs:old_int10h_seg /* vga attached? */
jnz chain_post_cursor /* if not, don't restore the cursor */
call set_current_cursor /* restore cursor if vga attached */
chain_post_cursor:
popaw
jmp do_old_int10h
/*
* pnp_sga_init
*
* handle PnP initialization of option rom
*
* es:di = pointer to PnP structure
* ax = indication as to which vectors should be hooked
* by specifying th type of boot device this has
* been selected as
* bit 7..3= reserved(0)
* bit 2 = 1 = connect as IPL (int 13h)
* bit 1 = 1 = connect as primary video (int 10h)
* bit 0 = 1 = connect as primary input (int 9h)
* bx = card select number (probably 0xffff)
* dx = read data port address (probably 0xffff)
*
* return:
* ax = initialization status
* bit 8 = 1 = IPL device supports int 13h block dev format
* bit 7 = 1 = Output device supports int 10h char output
* bit 6 = 1 = Input device supports int 9h char input
* bit 5..4 = 00 = no IPL device attached
* 01 = unknown whether or not IPL device attached
* 10 = IPL device attached (RPL devices have connection)
* 11 = reserved
* bit 3..2 = 00 = no display device attached
* 01 = unknown whether or not display device attached
* 10 = display device attached
* 11 = reserved
* bit 1..0 = 00 = no input device attached
* 01 = unknown whether or not input device attached
* 10 = input device attached
* 11 = reserved
*
* all registers preserved except %ax
*/
pnp_sga_init:
/* FIXME: this is *wrong* -- init only what bios says to init */
movw $0xca, %ax /* 0xca = attached int 10h, 9h display, input */
/*
* sga_init
*
* legacy option rom entry point
*
* all registers preserved
*/
sga_init:
/* this is probably paranoid about register preservation */
pushfw
cli /* more paranoia */
pushaw
pushw %ds
pushw %es
pushw $0
popw %es /* es = 0 */
pushw %cs
popw %ds /* ds = cs */
/* get original ISR */
movl %es:0x28, %eax /* eax = old irq 3/int 0bh */
movl %eax, old_irq3 /* save away old irq 4/int 0bh */
movl %es:0x2c, %eax /* eax = old irq 4/int 0ch */
movl %eax, old_irq4 /* save away old irq 4/int 0ch */
movl %es:0x40, %eax /* eax = old int 10h */
movl %eax, old_int10h /* save away old int 10h */
movl %es:0x50, %eax /* eax = old int 14h */
movl %eax, old_int14h /* save away old int 14h */
movl %es:0x58, %eax /* eax = old int 16h */
movl %eax, old_int16h /* save away old int 16h */
movw $irq3_isr, %es:0x28 /* new irq 3 offset */
movw %cs, %es:0x2a /* write new irq 3 seg */
movw $irq4_isr, %es:0x2c /* new irq 4 offset */
movw %cs, %es:0x2e /* write new irq 4 seg */
movw $int10h_isr, %es:0x40 /* new int 10h offset */
movw %cs, %es:0x42 /* write new int10h seg */
movw $int14h_isr, %es:0x50 /* new int 14h offset */
movw %cs, %es:0x52 /* write new int14h seg */
movw $int16h_isr, %es:0x58 /* new int 16h offset */
movw %cs, %es:0x5a /* write new int16h seg */
/* empty input buffer to prepare for terminal sizing */
call init_serial_port
input_clear_loop:
call get_byte
jnz input_clear_loop
movw $term_init_string, %si
call send_asciz_out
push $BDA_SEG
push $BDA_SEG
popw %ds /* ds = 0x40 */
popw %es /* es = 0x40 */
movw $BDA_CURSOR_BUF, %di
input_timeout_loop:
/* get input from terminal until timeout found */
/* store input at 40:50 - 40:5e (cursor pos) */
call poll_byte
jz input_timeout
stosb /* es:di */
cmpw $0x5f, %di /* 14 characters max */
jnz input_timeout_loop /* good for more data */
input_timeout:
xorb %al, %al /* nul terminate input */
stosb
cmpw $0x58, %di /* less than 8 chars? */
jc resize_end /* too small to have valid data */
movw $BDA_CURSOR_BUF, %si /* point to start */
lodsw /* ax = first 2 chars */
cmpw $0x5b1b, %ax /* was it "ESC[" ? */
jnz resize_end /* reply starts ESC[row;colR */
xorb %bl, %bl /* bl = ascii->int conversion */
input_first_number:
lodsb /* al = next char */
cmpb $0x30, %al
jc resize_end /* char < 0x30 invalid */
cmpb $0x3a, %al /* is char < 0x3a */
jnc input_semicolon
andb $0x0f, %al /* al = 0 - 9 */
movb %bl, %ah /* ah = last conversion */
aad /* ax = (al + ah * 10) & 0xff */
movb %al, %bl /* bl = row ascii->int conversion */
jmp input_first_number
input_semicolon:
/* at this point bl should contain rows, al = ; */
/* sanity check, bail if invalid */
cmpb $0x3b, %al
jnz resize_end /* invalid input found */
cmpb $0x0a, %bl /* less than 10 rows? */
jc suspect_loopback /* consider input invalid */
xorb %bh, %bh /* bh = col ascii->int conversion */
input_second_number:
lodsb /* al = next char */
cmpb $0x30, %al
jc resize_end /* char < 0x30 invalid */
cmpb $0x3a, %al /* is char < 0x3a */
jnc input_final_r
andb $0x0f, %al /* al = 0 - 9 */
movb %bh, %ah /* ah = last conversion */
aad /* ax = (al + ah * 10) & 0xff */
movb %al, %bh /* bh = ascii->int conversion */
jmp input_second_number
input_final_r:
cmpb $0x52, %al /* is al = 'R' ? */
jnz suspect_loopback /* invalid input found */
movb %bl, %cs:term_rows /* save away bl rows value */
cmpw $0xc000, %cs:old_int10h_seg /* vga attached? */
jz resize_end /* if so, leave term_cols at 80 */
movb %bh, %cs:term_cols /* save away bh cols value */
jmp resize_end
suspect_loopback:
/*
* characters were received that look like what we sent out
* at this point, assume that a loopback device was plugged in
* and disable any future serial port reads or writes, by pointing
* output to port 0x2e8 (COM4) instead of 0x3f8 -- it's expected
* that this is safe since a real port responds correctly and a
* missing port will respond with 0xff which will terminate the
* loop that waits for the "right" status on the port.
*/
movw $0x2e8, %cs:serial_port_base_address
resize_end:
/* clear (hopefully) overwritten cursor position buffer */
xorb %al, %al
movw $BDA_CURSOR_BUF, %di
movw $0x10, %cx
cld
rep
stosb /* fill 40:50 - 40:5f with 0 */
pushw %cs
popw %ds /* ds = cs */
call get_byte /* flush any remaining "wrong" input */
jnz resize_end
call send_crlf /* place cursor on start of last line */
movw $mfg_string, %si
call send_asciz_out
call send_crlf
movw $prod_string, %si
call send_asciz_out
call send_crlf
movw $long_version, %si
call send_asciz_out
call send_crlf
/* if vga attached, skip terminal message and bda setup... */
cmpw $0xc000, %cs:old_int10h_seg /* vga attached? */
jz post_bda_init_tail /* if so, don't modify BDA */
/* show detected terminal size, or default if none detected */
movw $term_info, %si
call send_asciz_out
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movb %cs:term_cols, %al
movb %al, BDA_COLS /* 40:4a = number of character cols */
movb $0, BDA_CURSOR_COL /* 40:51 = cursor0 col */
call send_number
movb $0x78, %al /* x */
call send_byte
movb %cs:term_rows, %al
movb %al, %ah
decb %ah /* ah = rows-1 */
movb %ah, BDA_ROWS /* 40:84 = num character rows - 1 */
movb %ah, BDA_CURSOR_ROW /* 40:50 = cursor0 row */
call send_number
call send_crlf
movb $3, BDA_MODE_NUM
movb $0x29, BDA_MODE_SEL
movw $VGA_IO_BASE, BDA_6845_ADDR
movw $0x4000, BDA_PAGE_SIZE /* 16KB per video page */
/* to avoid ansi colors every character, store last attribute */
movb $0x07, BDA_COLOR_VAL /* 07 = black bg, white fg */
movw %cs, %ax
movw $_start, BDA_ROM_OFF
movw %ax, BDA_ROM_SEG
post_bda_init_tail:
/* copy BDA rows/cols to sgabios location... */
/* if vga card is installed, reuse those values... */
/* if no vga card is installed, this shouldn't change anything */
pushw $BDA_SEG
popw %ds /* ds = 0x40 */
movb BDA_ROWS, %al
incb %al /* bda holds rows-1 */
movb %al, %cs:term_rows /* sgabios rows */
movb BDA_COLS, %ah
movb %ah, %cs:term_cols /* sgabios cols */
/* setup in-memory logging of console if desired... */
call setup_memconsole
/* setup logging of last 256 characters output, if ebda has room */
call sgabioslog_setup_ebda
movw $ebda_info, %si
call send_asciz_out
movw %cs:sgabios_ebda_logbuf_offset, %ax
xchgb %ah, %al
call send_number
movb $0x20, %al
call send_byte
movb %ah, %al
call send_number
call send_crlf
popw %es
popw %ds
popaw
popf
lret
_end_sgabios: