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X86 segmentation: apparently, the CPU can execute a data segment in some cases, used by LINK and CodeView, fixes #5283.

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OBattler
2025-03-19 07:54:54 +01:00
parent 0fd97c8427
commit 2cd99f0c70
1 changed files with 24 additions and 0 deletions
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24
src/cpu/x86seg.c
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@@ -1334,6 +1334,12 @@ pmoderetf(int is32, uint16_t off)
if (CPL == (seg & 0x0003)) {
x86seg_log("RETF CPL = RPL %04X\n", segdat[2]);
switch (segdat[2] & 0x1f00) {
case 0x1000:
case 0x1100:
case 0x1200:
case 0x1300:
/* Data segment, apparently valid when CPL is the same, used by MS LINK for DOS. */
fallthrough;
case 0x1800:
case 0x1900:
case 0x1a00:
@@ -1384,6 +1390,12 @@ pmoderetf(int is32, uint16_t off)
cycles -= timing_retf_pm;
} else {
switch (segdat[2] & 0x1f00) {
case 0x1000:
case 0x1100:
case 0x1200:
case 0x1300:
/* Data segment, apparently valid when CPL is the same, used by MS LINK for DOS. */
fallthrough;
case 0x1800:
case 0x1900:
case 0x1a00:
@@ -1605,6 +1617,12 @@ pmodeint(int num, int soft)
return;
}
switch (segdat2[2] & 0x1f00) {
case 0x1000:
case 0x1100:
case 0x1200:
case 0x1300:
/* Data segment, apparently valid when CPL is the same, used by MS CodeView for DOS. */
fallthrough;
case 0x1800:
case 0x1900:
case 0x1a00:
@@ -1983,6 +2001,12 @@ pmodeiret(int is32)
}
switch (segdat[2] & 0x1f00) {
case 0x1000:
case 0x1100:
case 0x1200:
case 0x1300:
/* Data segment, apparently valid when CPL is the same, used by MS CodeView for DOS. */
fallthrough;
case 0x1800:
case 0x1900:
case 0x1a00: