Implement TSS debug trap bit

Cacodemon345 · Jan 13, 2024 · a13a8ef · a13a8ef
1 parent b1c292a
commit a13a8ef
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Showing 3 changed files with 23 additions and 3 deletions.
diff --git a/src/cpu/386.c b/src/cpu/386.c
@@ -311,12 +311,12 @@ exec386_2386(int32_t cycs)
                 }
             } else if (trap) {
                 flags_rebuild();
+                dr[6] |= (trap == 2) ? 0x8000 : 0x4000;
                 trap = 0;
 #ifndef USE_NEW_DYNAREC
                 oldcs = CS;
 #endif
                 cpu_state.oldpc = cpu_state.pc;
-                dr[6] |= 0x4000;
                 x86_int(1);
             }
 

diff --git a/src/cpu/386_dynarec.c b/src/cpu/386_dynarec.c
@@ -268,6 +268,12 @@ exec386_dynarec_int(void)
     cpu_block_end = 0;
     x86_was_reset = 0;
 
+    if (trap == 2) {
+        /* Handle the T bit in the new TSS first. */
+        CPU_BLOCK_END();
+        goto block_ended;
+    }
+
     while (!cpu_block_end) {
 #    ifndef USE_NEW_DYNAREC
         oldcs  = CS;
@@ -321,13 +327,14 @@ exec386_dynarec_int(void)
             CPU_BLOCK_END();
     }
 
+block_ended:
     if (!cpu_state.abrt && trap) {
+        dr[6] |= (trap == 2) ? 0x8000 : 0x4000;
         trap = 0;
 #    ifndef USE_NEW_DYNAREC
         oldcs = CS;
 #    endif
         cpu_state.oldpc = cpu_state.pc;
-        dr[6] |= 0x4000;
         x86_int(1);
     }
 
@@ -542,7 +549,7 @@ exec386_dynarec_dyn(void)
 #    endif
                 CPU_BLOCK_END();
 
-            if (cpu_state.flags & T_FLAG)
+            if ((cpu_state.flags & T_FLAG) || (trap == 2))
                 CPU_BLOCK_END();
             if (smi_line)
                 CPU_BLOCK_END();

diff --git a/src/cpu/x86seg.c b/src/cpu/x86seg.c
@@ -78,6 +78,10 @@ x86seg_log(const char *fmt, ...)
 #    define x86seg_log(fmt, ...)
 #endif
 
+#ifdef USE_DYNAREC
+extern int cpu_block_end;
+#endif
+
 void
 #ifdef OPS_286_386
 x86_doabrt_2386(int x86_abrt)
@@ -2088,6 +2092,7 @@ taskswitch286(uint16_t seg, uint16_t *segdat, int is32)
     uint32_t      new_edi;
     uint32_t      new_pc;
     uint32_t      new_flags;
+    uint32_t      t_bit;
     uint32_t      addr;
     uint32_t     *segdat232 = (uint32_t *) segdat2;
     const x86seg *dt;
@@ -2189,6 +2194,7 @@ taskswitch286(uint16_t seg, uint16_t *segdat, int is32)
         new_fs  = readmemw(base, 0x58);
         new_gs  = readmemw(base, 0x5C);
         new_ldt = readmemw(base, 0x60);
+        t_bit   = readmemb(base, 0x64) & 1;
 
         cr0 |= 8;
 
@@ -2279,6 +2285,13 @@ taskswitch286(uint16_t seg, uint16_t *segdat, int is32)
         op_loadseg(new_ds, &cpu_state.seg_ds);
         op_loadseg(new_fs, &cpu_state.seg_fs);
         op_loadseg(new_gs, &cpu_state.seg_gs);
+
+        if (t_bit) {
+            trap = 2;
+#ifdef USE_DYNAREC
+            cpu_block_end = 1;
+#endif
+        }
     } else {
         if (limit < 43) {
             x86ts(NULL, seg);