From 170d19c2ad516c146762b8cf597ededa467495fc Mon Sep 17 00:00:00 2001 From: Stefan Reinauer Date: Thu, 26 Jul 2012 15:48:17 -0700 Subject: x86emu: fix jump_near_IMM to handle DATA: flag correctly 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. Imported from: http://cgit.freedesktop.org/xorg/xserver/commit/hw/xfree86/x86emu?id=cc2c73ddcb4370a7c3ad439cda4da825156c26c9 Signed-off-by: Stefan Reinauer Change-Id: Id08ead9b17468cf19ede45508e5dcc50e45b5acf Signed-off-by: Luc Verhaegen Tested-by: Luc Verhaegen Reviewed-by: Adam Jackson Signed-off-by: Keith Packard Reviewed-on: http://review.coreboot.org/1365 Tested-by: build bot (Jenkins) Reviewed-by: Anton Kochkov Reviewed-by: Patrick Georgi --- src/devices/oprom/x86emu/ops.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/src/devices/oprom/x86emu/ops.c b/src/devices/oprom/x86emu/ops.c index 536b4041b2..6917a08162 100644 --- a/src/devices/oprom/x86emu/ops.c +++ b/src/devices/oprom/x86emu/ops.c @@ -4301,16 +4301,25 @@ 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", ip); - JMP_TRACE(M.x86.saved_cs, M.x86.saved_ip, M.x86.R_CS, ip, " NEAR "); - 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); + JMP_TRACE(M.x86.saved_cs, M.x86.saved_ip, M.x86.R_CS, ip, " NEAR "); + 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); + JMP_TRACE(M.x86.saved_cs, M.x86.saved_ip, M.x86.R_CS, ip, " NEAR "); + TRACE_AND_STEP(); + M.x86.R_IP = (u16)ip; + } DECODE_CLEAR_SEGOVR(); END_OF_INSTR(); } -- cgit v1.2.3