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| author | Kevin O'Connor <kevin@koconnor.net> | 2014-02-05 22:47:29 -0500 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2014-02-05 23:15:27 -0500 |
| commit | 8032b8a0fec550de5cb2f7d37aa031cebc2200c3 (patch) | |
| tree | b10eb99deec5f846c7b35b7bb0bc99c3a5e456a7 /vgasrc | |
| parent | 20dc419306701354f17abc8fe5d8eb467a009470 (diff) | |
| download | seabios-hppa-8032b8a0fec550de5cb2f7d37aa031cebc2200c3.zip seabios-hppa-8032b8a0fec550de5cb2f7d37aa031cebc2200c3.tar.gz seabios-hppa-8032b8a0fec550de5cb2f7d37aa031cebc2200c3.tar.bz2 | |
vgabios: Attempt to detect old x86emu and force a fault.
Check for cases where the leal instruction does not work. This
instruction is known to not be emulated properly on old versions of
x86emu. If a broken version of x86emu is found, force a fault that
x86emu will easily detect. This should help prevent soft failures
when running old software.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Diffstat (limited to 'vgasrc')
| -rw-r--r-- | vgasrc/vgaentry.S | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/vgasrc/vgaentry.S b/vgasrc/vgaentry.S index 9854448..6e31c4e 100644 --- a/vgasrc/vgaentry.S +++ b/vgasrc/vgaentry.S @@ -45,9 +45,26 @@ _rom_header_signature: * Entry points ****************************************************************/ - // This macro is the same as ENTRY_ARG except the "calll" - // instruction is avoided to work around known issues in the - // emulation of some versions of x86emu. + // Force a fault if found to be running on broken x86emu versions. + DECLFUNC x86emu_fault +x86emu_fault: +1: hlt + jmp 1b + + // This macro implements a call while avoiding instructions + // that old versions of x86emu have problems with. + .macro VGA_CALLL cfunc + // Make sure leal instruction works. + movl $0x8000, %ecx + leal (%ecx, %ecx, 1), %ecx + cmpl $0x10000, %ecx + jne x86emu_fault + // Use callw instead of calll + push %ax + callw \cfunc + .endm + + // This macro is the same as ENTRY_ARG except VGA_CALLL is used. .macro ENTRY_ARG_VGA cfunc cli cld @@ -57,7 +74,7 @@ _rom_header_signature: movl %esp, %ebx // Backup %esp, then zero high bits movzwl %sp, %esp movl %esp, %eax // First arg is pointer to struct bregs - pushw %ax ; callw \cfunc + VGA_CALLL \cfunc movl %ebx, %esp // Restore %esp (including high bits) POPBREGS .endm @@ -103,7 +120,7 @@ entry_10_extrastack: movw %ds, %dx // Setup %ss/%esp and call function movw %dx, %ss movl %eax, %esp - pushw %ax ; callw handle_10 + VGA_CALLL handle_10 movl %esp, %eax // Restore registers and return movw BREGS_size+4(%eax), %ss |