simx86: handle PM far calls via Sim_helper()

Which can separate calls to selector checks and sets, so
all exceptions can be checked and then the old CS:EIP
is pushed before the new CS:EIP is set.

Author: bartoldeman

src/base/emu-i386/simx86/codegen-sim.c

@@ -2977,6 +2977,14 @@ static __inline__ void SetCPU_WL(int m, signed char o, unsigned long v)
 	unsigned int __res = sim_read_dword(LONG_SS + sp); \
 	sp += 4; sp &= TheCPU.StackMask; __res; })
 
+#define PUSHw(sp,w) ({ \
+	sp -= 2; sp &= TheCPU.StackMask; \
+	sim_write_word(LONG_SS + sp, w); })
+
+#define PUSHl(sp,l) ({ \
+	sp -= 4; sp &= TheCPU.StackMask; \
+	sim_write_dword(LONG_SS + sp, l); })
+
 /* This generic helper function is called from JIT generated code and from
  * Gen_sim to simulate hard-to-compile and rarely used ops.
  * parameters:
@@ -3093,6 +3101,33 @@ static unsigned int _Sim_helper(unsigned int mem_ref, unsigned int data, int mod
 					    inum, _AX, _CS, _IP);
 			break;
 		       }
+/*9a*/	case CALLl: {	/* restartable */
+			unsigned int oldcs = TheCPU.cs;
+			unsigned int oldeip = arg;
+			unsigned int newcs = data;
+			unsigned int sp;
+			int e = SetSegProt_check(Ofs_CS, newcs);
+			if (e > 0)
+				break;
+			sp = rESP;
+			if (mode&DATA16) {
+				PUSHw(sp,oldcs);
+				PUSHw(sp,oldeip);
+			}
+			else {
+				PUSHl(sp,oldcs);
+				PUSHl(sp,oldeip);
+			}
+			if (debug_level('e')>2) {
+				dbug_printf("CALL_FAR: ret=%04x:%08x\n  calling:      cs=%04x\n",
+					    oldcs,oldeip,newcs);
+			}
+			rESP = sp | (rESP&~TheCPU.StackMask);
+			// -1 means cached, nothing to set
+			if (e == 0)
+				SetSegProt_set(Ofs_CS, data);
+			break;
+			}
 /*ca*/	case RETlisp:
 /*cb*/	case RETl:
 /*cf*/	case IRET: {	/* restartable */

src/base/emu-i386/simx86/interp.c

@@ -295,16 +295,16 @@ static unsigned int JumpGen(unsigned int P2, unsigned int Interp_LONG_CS,
 		break;
 	case CALLl: {   /* call far */
 		unsigned short jcs = FetchW(P2 + pskip - 2);
-		Gen(L_IMM_R1, mode|DATA16, jcs);
-		if (REALADDR())
+		Gen(L_IMM_R1, mode&~DATA16, jcs);
+		if (REALADDR()) {
 		    AddrGen(A_SR_SH4, mode, Ofs_CS, Ofs_XCS);
-		else
-		    /* check if new cs is valid, load if so */
-		    AddrGen(A_SR_PROT, mode, Ofs_CS, P2);
-		/* ok, now push old cs (returned by A_SR_*):eip */
-		Gen(O_PUSH, mode);
-		if (!REALADDR()) {
-		    Gen(O_PUSHI, mode, d_nt);
+		    /* ok, now push old cs (returned by A_SR_SH4):eip */
+		    Gen(O_PUSH, mode);
+		    /* fall through */
+		}
+		else {
+		    /* handle PM far calls via Sim_helper() */
+		    Gen(O_SIM, mode, opc, d_nt, P2);
 		    /* transfer to new PC (indirect jmp) */
 		    Gen(L_IMM_R1, mode, d_t);
 		    Gen(JMP_INDIRECT, mode);
@@ -2185,13 +2185,19 @@ intop3b:		{ int op = ArOpsFR[D_MO(opc)];
 					Gen(L_LXS2, _mode);
 					if (REALADDR())
 					    AddrGen(A_SR_SH4, _mode, Ofs_CS, Ofs_XCS);
-					else
+					else if (REG1==Ofs_BP) /* PM JMP */
 					    AddrGen(A_SR_PROT, _mode, Ofs_CS, P0);
 					if (REG1==Ofs_BX) {
 					    /* ok, now push old cs:eip */
 					    oip = PC + len - Interp_LONG_CS;
-					    Gen(O_PUSH, _mode);
-					    Gen(O_PUSHI, _mode, oip);
+					    if (REALADDR()) {
+						Gen(O_PUSH, _mode);
+						Gen(O_PUSHI, _mode, oip);
+					    }
+					    else {
+						/* handle PM far calls via Sim_helper() */
+						Gen(O_SIM, _mode, CALLl, oip, P0);
+					    }
 					}
 					Gen(L_DI_R1, _mode);
 					PC = JumpGen(PC, Interp_LONG_CS, _mode,

src/base/emu-i386/simx86/protmode.c

@@ -195,7 +195,7 @@ static int _SetSegProt_check(int ofs, unsigned long sel)
 	return 0;
 }
 
-static int SetSegProt_check(int ofs, unsigned long sel)
+int SetSegProt_check(int ofs, unsigned long sel)
 {
 	int e = _SetSegProt_check(ofs, sel);
 	if (e > 0) {
@@ -205,7 +205,7 @@ static int SetSegProt_check(int ofs, unsigned long sel)
 	return e;
 }
 
-static void SetSegProt_set(int ofs, unsigned long sel)
+void SetSegProt_set(int ofs, unsigned long sel)
 {
 	static char buf[4];
 	unsigned short wFlags = GetSelectorFlags(sel);

src/base/emu-i386/simx86/protmode.h

@@ -228,6 +228,8 @@ typedef struct {
 //
 extern unsigned char e_ofsseg(int ofs);
 //
+int SetSegProt_check(int ofs, unsigned long sel);
+void SetSegProt_set(int ofs, unsigned long sel);
 void SetSegProt(int ofs, unsigned long sel);
 int SetSegProt_helper(unsigned short sv, int ofs);
 int SetSegReal(unsigned short sel, int ofs);