diff options
Diffstat (limited to 'qemu/roms/openbios/arch/sparc32/wuf.S')
| -rw-r--r-- | qemu/roms/openbios/arch/sparc32/wuf.S | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/qemu/roms/openbios/arch/sparc32/wuf.S b/qemu/roms/openbios/arch/sparc32/wuf.S new file mode 100644 index 000000000..853fc7322 --- /dev/null +++ b/qemu/roms/openbios/arch/sparc32/wuf.S @@ -0,0 +1,154 @@ +/* + * Window fill (underflow) trap, based on code from Sparclinux. + * + * Copyright (C) 1995 David S. Miller + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + * MA 02110-1301, USA. + */ + +// #include <psr.h> +// #include <asi.h> + +/* Reg_window offsets */ +#define RW_L0 0x00 +#define RW_L1 0x04 +#define RW_L2 0x08 +#define RW_L3 0x0c +#define RW_L4 0x10 +#define RW_L5 0x14 +#define RW_L6 0x18 +#define RW_L7 0x1c +#define RW_I0 0x20 +#define RW_I1 0x24 +#define RW_I2 0x28 +#define RW_I3 0x2c +#define RW_I4 0x30 +#define RW_I5 0x34 +#define RW_I6 0x38 +#define RW_I7 0x3c + +/* Load a register window from the area beginning at %reg. */ +#define LOAD_WINDOW(reg) \ + ldd [%reg + RW_L0], %l0; \ + ldd [%reg + RW_L2], %l2; \ + ldd [%reg + RW_L4], %l4; \ + ldd [%reg + RW_L6], %l6; \ + ldd [%reg + RW_I0], %i0; \ + ldd [%reg + RW_I2], %i2; \ + ldd [%reg + RW_I4], %i4; \ + ldd [%reg + RW_I6], %i6; + +#define WRITE_PAUSE nop; nop; nop; /* Have to do this after %wim/%psr chg */ + +/* Just like the overflow handler we define macros for registers + * with fixed meanings in this routine. + */ +#define t_psr l0 +#define t_pc l1 +#define t_npc l2 +#define t_wim l3 +/* Don't touch the above registers or else you die horribly... */ + +/* Now macros for the available scratch registers in this routine. */ +#define twin_tmp1 l4 +#define twin_tmp2 l5 + + .text + .align 4 + + /* The trap entry point has executed the following: + * + * rd %psr, %l0 + * rd %wim, %l3 + * b fill_window_entry + * andcc %l0, PSR_PS, %g0 + */ + + /* To get an idea of what has just happened to cause this + * trap take a look at this diagram: + * + * 1 2 3 4 <-- Window number + * ---------- + * T O W I <-- Symbolic name + * + * O == the window that execution was in when + * the restore was attempted + * + * T == the trap itself has save'd us into this + * window + * + * W == this window is the one which is now invalid + * and must be made valid plus loaded from the + * stack + * + * I == this window will be the invalid one when we + * are done and return from trap if successful + */ + + /* BEGINNING OF PATCH INSTRUCTIONS */ + + /* On 7-window Sparc the boot code patches fnwin_patch1 + * with the following instruction. + */ + .globl fnwin_patch1_7win, fnwin_patch2_7win +fnwin_patch1_7win: srl %t_wim, 6, %twin_tmp2 +fnwin_patch2_7win: and %twin_tmp1, 0x7f, %twin_tmp1 + /* END OF PATCH INSTRUCTIONS */ + + + .globl fill_window_entry, fnwin_patch1, fnwin_patch2 +fill_window_entry: + /* LOCATION: Window 'T' */ + + /* Compute what the new %wim is going to be if we retrieve + * the proper window off of the stack. + */ + sll %t_wim, 1, %twin_tmp1 +fnwin_patch1: srl %t_wim, 7, %twin_tmp2 + or %twin_tmp1, %twin_tmp2, %twin_tmp1 +fnwin_patch2: and %twin_tmp1, 0xff, %twin_tmp1 + + wr %twin_tmp1, 0x0, %wim /* Make window 'I' invalid */ + + restore %g0, %g0, %g0 /* Restore to window 'O' */ + + /* Trapped from kernel, we trust that the kernel does not + * 'over restore' sorta speak and just grab the window + * from the stack and return. Easy enough. + */ + /* LOCATION: Window 'O' */ + + restore %g0, %g0, %g0 + WRITE_PAUSE + + /* LOCATION: Window 'W' */ + + LOAD_WINDOW(sp) /* Load it up */ + + /* Spin the wheel... */ + save %g0, %g0, %g0 + save %g0, %g0, %g0 + /* I'd like to buy a vowel please... */ + + /* LOCATION: Window 'T' */ + + /* Now preserve the condition codes in %psr, pause, and + * return from trap. This is the simplest case of all. + */ + wr %t_psr, 0x0, %psr + WRITE_PAUSE + + jmp %t_pc + rett %t_npc |