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x86seg.c: Make sure not to read beyond the end of the stack segment on stack transfers, fixes erroneous page faults when transferring 16-bit stacks to 32-bit stacks, fixes OS/2 2.0 build 6.141.

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OBattler
2024-07-02 01:47:42 +02:00
parent 7d18b0ca07
commit eab504f388
1 changed files with 40 additions and 5 deletions
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45
src/cpu/x86seg.c
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@@ -896,7 +896,7 @@ loadcscall(uint16_t seg)
uint32_t oldsp;
uint32_t newsp;
uint32_t oldsp2;
uint16_t tempw;
uint32_t oldss_limit_high = cpu_state.seg_ss.limit_high;
const x86seg *dt;
if ((msw & 1) && !(cpu_state.eflags & VM_FLAG)) {
@@ -1125,7 +1125,31 @@ loadcscall(uint16_t seg)
}
if (count) {
while (count--) {
PUSHL(readmeml(oldssbase, oldsp + (count << 2)));
uint32_t temp_val;
switch (oldss_limit_high - oldsp - (count << 2)) {
default:
case 3:
/* We are at least an entire DWORD away from the limit,
read long. */
PUSHL(readmeml(oldssbase, oldsp + (count << 2)));
break;
case 2:
/* We are 3 bytes away from the limit,
read word + byte. */
temp_val = readmemw(oldssbase, oldsp + (count << 2));
temp_val |= (readmemb(oldssbase, oldsp +
(count << 2) + 2) << 16);
PUSHL(temp_val);
break;
case 1:
/* We are a WORD away from the limit, read word. */
PUSHL(readmemw(oldssbase, oldsp + (count << 2)));
break;
case 0:
/* We are a BYTE away from the limit, read byte. */
PUSHL(readmemb(oldssbase, oldsp + (count << 2)));
break;
}
if (cpu_state.abrt) {
SS = oldss;
ESP = oldsp2;
@@ -1152,9 +1176,20 @@ loadcscall(uint16_t seg)
x86seg_log("Write SP to %04X:%04X\n", SS, SP);
if (count) {
while (count--) {
tempw = readmemw(oldssbase, (oldsp & 0xffff) + (count << 1));
x86seg_log("PUSH %04X\n", tempw);
PUSHW(tempw);
switch (oldss_limit_high - (oldsp & 0xffff) - (count << 1)) {
default:
case 1:
/* We are at least an entire WORD away from the limit,
read word. */
PUSHW(readmemw(oldssbase, (oldsp & 0xffff) +
(count << 1)));
break;
case 0:
/* We are a BYTE away from the limit, read byte. */
PUSHW(readmemb(oldssbase, (oldsp & 0xffff) +
(count << 1)));
break;
}
if (cpu_state.abrt) {
SS = oldss;
ESP = oldsp2;