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Implement special selector pushing behavior and improve the opcode length heuristic for CS limit checks, fixes #4552.

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OBattler
2024-06-23 02:28:22 +02:00
parent 499a4e1d77
commit bbe035b62a
4 changed files with 62 additions and 12 deletions
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14
src/cpu/386.c
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@@ -212,11 +212,11 @@ fetch_ea_16_long(uint32_t rmdat)
#define CLOCK_CYCLES_ALWAYS(c) cycles -= (c)
#define CHECK_READ_CS(size) \
if ((cpu_state.pc < cpu_state.seg_cs.limit_low) || \
((cpu_state.pc + size - 1) > cpu_state.seg_cs.limit_high)) \
x86gpf("Limit check (READ)", 0); \
if (msw & 1 && !(cpu_state.eflags & VM_FLAG) && !(cpu_state.seg_cs.access & 0x80)) \
x86np("Read from seg not present", cpu_state.seg_cs.seg & 0xfffc); \
else if ((cpu_state.pc < cpu_state.seg_cs.limit_low) || \
((cpu_state.pc + size - 1) > cpu_state.seg_cs.limit_high)) \
x86gpf("Limit check (READ CS)", 0);
#include "386_ops.h"
@@ -261,7 +261,13 @@ exec386_2386(int32_t cycs)
fetchdat = fastreadl_fetch(cs + cpu_state.pc);
ol = opcode_length[fetchdat & 0xff];
CHECK_READ_CS(MIN(ol, 4));
if ((ol == 3) && opcode_has_modrm[fetchdat & 0xff] && (((fetchdat >> 14) & 0x03) == 0x03))
ol = 2;
if (cpu_16bitbus) {
CHECK_READ_CS(MIN(ol, 2));
} else {
CHECK_READ_CS(MIN(ol, 4));
}
ins_fetch_fault = cpu_386_check_instruction_fault();
/* Breakpoint fault has priority over other faults. */