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bits 16
org 100h
_start:
; first check for SYSLINUX
mov ah, 30h
int 21h
cmp eax, 59530000h
jne .not_syslinux
cmp ebx, 4c530000h
jne .not_syslinux
cmp ecx, 4e490000h
jne .not_syslinux
cmp edx, 58550000h
jne .not_syslinux
; now get syslinux version
mov ax, 0001h
int 22h
push cx
push dx
push di
push si
push es
; print version string
mov dx, str_version
mov ah, 09h
int 21h
pop es
pop bx
push es
mov ax, 0002h
int 22h
; print copyright string
mov dx, str_copyright
mov ah, 09h
int 21h
pop es
pop bx
mov ax, 0002h
int 22h
; print syslinux derivative id
mov dx, str_derivative
mov ah, 09h
int 21h
pop ax
call print_hex_byte
; print version number
mov dx, str_version_num
mov ah, 09h
int 21h
pop cx
push cx
mov ax, cx
and ax, 0FFh
call print_dec_word
mov dl, '.'
mov ah, 02h
int 21h
pop cx
mov ax, cx
shr ax, 8
call print_dec_word
ret
.not_syslinux:
mov dx, str_not_syslinux
mov ah, 09h
int 21h
ret
; input: al = byte to print in hex
print_hex_byte:
push ax
shr al, 4
call print_hex_nybble
pop ax
call print_hex_nybble
ret
; input: bottom half of al = nybble to print in hex
print_hex_nybble:
push ax
mov bl, al
and bx, 1111b
mov dl, [str_hex + bx]
mov ah, 02h
int 21h
pop ax
ret
str_hex: db "01234567890abcdef"
; input: ax = word to print
print_dec_word:
mov cx, 10
mov word [.count], 0
.loop:
xor dx, dx
div cx
inc word [.count]
push dx
test ax, ax
jnz .loop
.print:
pop dx
add dx, '0'
mov ah, 02h
int 21h
dec word [.count]
jnz .print
ret
.count: dw 0
str_not_syslinux: db "Not SYSLINUX or derivative (running on DOS?)$"
str_version: db "Version: $"
str_copyright: db 10, "Copyright: $"
str_derivative: db 10, "Derivative ID: 0x$"
str_version_num: db 10, "Version number: $"
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