Clean invalid selectors on the pop %xs from the STACKFRAME itself

instead of using linked list hack.

memory/selector.c

@@ -162,7 +162,6 @@ void SELECTOR_FreeBlock( WORD sel, WORD count )
 {
     WORD i, nextsel;
     ldt_entry entry;
-    STACK16FRAME *frame;
 
     TRACE(selector, "(%04x,%d)\n", sel, count );
     sel &= ~(__AHINCR - 1);  /* clear bottom bits of selector */
@@ -190,16 +189,6 @@ void SELECTOR_FreeBlock( WORD sel, WORD count )
         LDT_SetEntry( i, &entry );
         ldt_flags_copy[i] &= ~LDT_FLAGS_ALLOCATED;
     }
-
-    /* Clear the saved 16-bit selector */
-    frame = CURRENT_STACK16;
-    while (frame && frame->frame32)
-    {
-        if ((frame->ds >= sel) && (frame->ds < nextsel)) frame->ds = 0;
-        if ((frame->es >= sel) && (frame->es < nextsel)) frame->es = 0;
-        if ((frame->fs >= sel) && (frame->fs < nextsel)) frame->fs = 0;
-        frame = PTR_SEG_TO_LIN( frame->frame32->frame16 );
-    }
 }
 
 

miscemu/instr.c

@@ -11,6 +11,7 @@
 #include "dosexe.h"
 #include "miscemu.h"
 #include "sig_context.h"
+#include "selectors.h"
 #include "debug.h"
 
 
@@ -33,6 +34,9 @@
     (IS_SELECTOR_SYSTEM(SS_sig(context)) ? (void *)ESP_sig(context) : \
      (PTR_SEG_OFF_TO_LIN(SS_sig(context),STACK_sig(context)))))
 
+/* For invalid registers fixup */
+extern DWORD CallFrom16_Start,CallFrom16_End;
+
 
 /***********************************************************************
  *           INSTR_ReplaceSelector
@@ -386,9 +390,24 @@ BOOL32 INSTR_EmulateInstruction( SIGCONTEXT *context )
         case 0x1f: /* pop ds */
             {
                 WORD seg = *(WORD *)STACK_PTR( context );
+
+		/* Sometimes invalid selectors are left on the stackframe 
+		 * pop them if needed.
+		 */
+		if ((EIP_sig(context)>=(DWORD)&CallFrom16_Start) &&
+		    (EIP_sig(context)<(DWORD)&CallFrom16_End)
+		) {
+                    switch(*instr) {
+                    case 0x07: ES_sig(context) = 0; break;
+                    case 0x17: SS_sig(context) = 0; break;
+                    case 0x1f: DS_sig(context) = 0; break;
+                    }
+                    STACK_sig(context) += long_op ? 4 : 2;
+                    EIP_sig(context) += prefixlen + 1;
+		    return TRUE;
+		}
                 if ((seg = INSTR_ReplaceSelector( context, seg )) != 0)
-                {
+                {                    switch(*instr)
-                    switch(*instr)
                     {
                     case 0x07: ES_sig(context) = seg; break;
                     case 0x17: SS_sig(context) = seg; break;
@@ -426,6 +445,14 @@ BOOL32 INSTR_EmulateInstruction( SIGCONTEXT *context )
             case 0xa1: /* pop fs */
                 {
                     WORD seg = *(WORD *)STACK_PTR( context );
+ 		    if ((EIP_sig(context)>=(DWORD)&CallFrom16_Start) &&
+ 		        (EIP_sig(context)<(DWORD)&CallFrom16_End)
+ 		    ) {
+ 		    	FS_sig(context) = 0;
+ 			STACK_sig(context) += long_op ? 4 : 2;
+ 			EIP_sig(context) += prefixlen + 1;
+ 			return TRUE;
+ 		    }
                     if ((seg = INSTR_ReplaceSelector( context, seg )) != 0)
                     {
                         FS_sig(context) = seg;
@@ -441,6 +468,14 @@ BOOL32 INSTR_EmulateInstruction( SIGCONTEXT *context )
             case 0xa9: /* pop gs */
                 {
                     WORD seg = *(WORD *)STACK_PTR( context );
+		    if ((EIP_sig(context)>=(DWORD)&CallFrom16_Start) &&
+		        (EIP_sig(context)<(DWORD)&CallFrom16_End)
+		    ) {
+		    	GS_sig(context) = 0;
+			STACK_sig(context) += long_op ? 4 : 2;
+			EIP_sig(context) += prefixlen + 1;
+			return TRUE;
+		    }
                     if ((seg = INSTR_ReplaceSelector( context, seg )) != 0)
                     {
                         GS_sig(context) = seg;

tools/build.c

@@ -2506,6 +2506,8 @@ static int BuildCallFrom16( FILE *outfile, char * outname, int argc, char *argv[
     fprintf( outfile, "\t.align 4\n" );
     fprintf( outfile, "Code_Start:\n\n" );
 #endif
+    fprintf( outfile, PREFIX"CallFrom16_Start:\n" );
+    fprintf( outfile, "\t.globl "PREFIX"CallFrom16_Start\n" );
 
     /* Build the callback functions */
 
@@ -2526,6 +2528,8 @@ static int BuildCallFrom16( FILE *outfile, char * outname, int argc, char *argv[
             fprintf( outfile, STRING " \"%s\\0\"\n", argv[i] + 7 );
         }
     }
+    fprintf( outfile, PREFIX"CallFrom16_End:\n" );
+    fprintf( outfile, "\t.globl "PREFIX"CallFrom16_End\n" );
 
 #ifdef USE_STABS
     fprintf( outfile, "\t.text\n");