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authorLuc Verhaegen <libv@skynet.be>2010-10-24 21:57:06 (GMT)
committerKeith Packard <keithp@keithp.com>2010-11-10 22:56:57 (GMT)
commitcc2c73ddcb4370a7c3ad439cda4da825156c26c9 (patch)
tree11d87151a51673cf573966d3e04ee11c66d1e34b /hw/xfree86/x86emu
parentbe7cf14c365c8ee0d69c4335e01316bcfcba69a4 (diff)
x86emu: fix jump_near_IMM to handle DATA: flag correctly.
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=24348 Before (data flag ignored -> broken): 66 DATA: e944f1 JMP 1ff6 After (fixed): 66 DATA: e944f1ffff JMP 00001ff8 This subtle difference in the length of decoded instruction meant that the VBE call jumped to the routine setting AX=0x14F (VBE Failed) instead of the routine that set AX=0x4F (VBE success). The ability to run the same code in vm86 significantly aided the debugging of this issue. Those X.org developers who would like to drop vm86 better take special care towards _all_ vesa bugs, as those will expose further issues. Patch applies easily to even xserver 1.4.2. Signed-off-by: Luc Verhaegen <libv@skynet.be> Tested-by: Luc Verhaegen <libv@skynet.be> Reviewed-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'hw/xfree86/x86emu')
-rw-r--r--hw/xfree86/x86emu/ops.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/hw/xfree86/x86emu/ops.c b/hw/xfree86/x86emu/ops.c
index 21a0347..c6b2f0a 100644
--- a/hw/xfree86/x86emu/ops.c
+++ b/hw/xfree86/x86emu/ops.c
@@ -9691,15 +9691,23 @@ Handles opcode 0xe9
****************************************************************************/
static void x86emuOp_jump_near_IMM(u8 X86EMU_UNUSED(op1))
{
- int ip;
+ u32 ip;
START_OF_INSTR();
DECODE_PRINTF("JMP\t");
- ip = (s16)fetch_word_imm();
- ip += (s16)M.x86.R_IP;
- DECODE_PRINTF2("%04x\n", (u16)ip);
- TRACE_AND_STEP();
- M.x86.R_IP = (u16)ip;
+ if (M.x86.mode & SYSMODE_PREFIX_DATA) {
+ ip = (u32)fetch_long_imm();
+ ip += (u32)M.x86.R_EIP;
+ DECODE_PRINTF2("%08x\n", (u32)ip);
+ TRACE_AND_STEP();
+ M.x86.R_EIP = (u32)ip;
+ } else {
+ ip = (s16)fetch_word_imm();
+ ip += (s16)M.x86.R_IP;
+ DECODE_PRINTF2("%04x\n", (u16)ip);
+ TRACE_AND_STEP();
+ M.x86.R_IP = (u16)ip;
+ }
DECODE_CLEAR_SEGOVR();
END_OF_INSTR();
}