mirror/86Box
1
0
Fork 0
mirror of https://github.com/86Box/86Box.git synced 2026-02-22 01:25:33 -07:00
Code Issues Packages Projects Releases Activity

Merge pull request #6561 from snowkat/grp4-ud

Browse Source 
CPU: Restrict allowed opcodes in INC/DEC Grp4
This commit is contained in:
Miran Grča
2025-12-15 05:01:37 +01:00
committed by GitHub
parent 036a0186c1 ca9eb9acb9
commit 97cd239120
1 changed files with 34 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

54
src/cpu/x86_ops_inc_dec.h
View File

@@ -56,16 +56,23 @@ opINCDEC_b_a16(uint32_t fetchdat)
if (cpu_state.abrt)
return 1;
if (rmdat & 0x38) {
seteab(temp - 1);
if (cpu_state.abrt)
return 1;
setsub8nc(temp, 1);
} else {
seteab(temp + 1);
if (cpu_state.abrt)
return 1;
setadd8nc(temp, 1);
switch (rmdat & 0x38) {
case 0: /* INC r/m8 */
seteab(temp + 1);
if (cpu_state.abrt)
return 1;
setadd8nc(temp, 1);
break;
case 0x8: /* DEC r/m8 */
seteab(temp - 1);
if (cpu_state.abrt)
return 1;
setsub8nc(temp, 1);
break;
default:
cpu_state.pc = cpu_state.oldpc;
x86illegal();
break;
}
CLOCK_CYCLES((cpu_mod == 3) ? timing_rr : timing_mm);
PREFETCH_RUN((cpu_mod == 3) ? timing_rr : timing_mm, 2, rmdat, (cpu_mod == 3) ? 0 : 1, 0, (cpu_mod == 3) ? 0 : 1, 0, 0);
@@ -83,16 +90,23 @@ opINCDEC_b_a32(uint32_t fetchdat)
if (cpu_state.abrt)
return 1;
if (rmdat & 0x38) {
seteab(temp - 1);
if (cpu_state.abrt)
return 1;
setsub8nc(temp, 1);
} else {
seteab(temp + 1);
if (cpu_state.abrt)
return 1;
setadd8nc(temp, 1);
switch (rmdat & 0x38) {
case 0: /* INC r/m8 */
seteab(temp + 1);
if (cpu_state.abrt)
return 1;
setadd8nc(temp, 1);
break;
case 0x8: /* DEC r/m8 */
seteab(temp - 1);
if (cpu_state.abrt)
return 1;
setsub8nc(temp, 1);
break;
default:
cpu_state.pc = cpu_state.oldpc;
x86illegal();
break;
}
CLOCK_CYCLES((cpu_mod == 3) ? timing_rr : timing_mm);
PREFETCH_RUN((cpu_mod == 3) ? timing_rr : timing_mm, 2, rmdat, (cpu_mod == 3) ? 0 : 1, 0, (cpu_mod == 3) ? 0 : 1, 0, 1);