From e624ccc2ff32e081f9961ace54fbbcc035c99019 Mon Sep 17 00:00:00 2001
From: Jonathan Campbell <jonathan@castus.tv>
Date: Sat, 26 Oct 2013 11:46:03 -0700
Subject: [PATCH] change vm86 force I/O to generate code once then use lookup
 table. this works around the dynamic core's cachine and other weirdness.

---
 src/cpu/cpu.cpp | 91 ++++++++++++++++++++++++++-----------------------
 1 file changed, 49 insertions(+), 42 deletions(-)

diff --git a/src/cpu/cpu.cpp b/src/cpu/cpu.cpp
index abe2349c7..971ba7ffb 100644
--- a/src/cpu/cpu.cpp
+++ b/src/cpu/cpu.cpp
@@ -2578,14 +2578,57 @@ CPU_Decoder *CPU_IndexDecoderType( Bit16u decoder_idx )
 
 static Bitu vm86_fake_io_seg = 0xF000;	/* unused area in BIOS for IO instruction */
 static Bitu vm86_fake_io_off = 0x0700;
+static Bitu vm86_fake_io_offs[3*2]={0};	/* offsets from base off because of dynamic core cache */
+
+static void init_vm86_fake_io() {
+	Bitu phys = (vm86_fake_io_seg << 4) + vm86_fake_io_off;
+	Bitu wo = 0;
+
+	if (vm86_fake_io_offs[0] != 0)
+		return;
+
+	fprintf(stderr,"Initializing vm86 fake I/O\n");
+
+	/* read */
+	vm86_fake_io_offs[0] = vm86_fake_io_off + wo;
+	phys_writeb(phys+wo+0x00,(Bit8u)0xEC);	/* IN AL,DX */
+	phys_writeb(phys+wo+0x01,(Bit8u)0xCB);	/* RETF */
+	wo += 2;
+
+	vm86_fake_io_offs[1] = vm86_fake_io_off + wo;
+	phys_writeb(phys+wo+0x00,(Bit8u)0xED);	/* IN AX,DX */
+	phys_writeb(phys+wo+0x01,(Bit8u)0xCB);	/* RETF */
+	wo += 2;
+
+	vm86_fake_io_offs[2] = vm86_fake_io_off + wo;
+	phys_writeb(phys+wo+0x00,(Bit8u)0x66);	/* IN EAX,DX */
+	phys_writeb(phys+wo+0x01,(Bit8u)0xED);
+	phys_writeb(phys+wo+0x02,(Bit8u)0xCB);	/* RETF */
+	wo += 3;
+
+	/* write */
+	vm86_fake_io_offs[3] = vm86_fake_io_off + wo;
+	phys_writeb(phys+wo+0x00,(Bit8u)0xEE);	/* OUT DX,AL */
+	phys_writeb(phys+wo+0x01,(Bit8u)0xCB);	/* RETF */
+	wo += 2;
+
+	vm86_fake_io_offs[4] = vm86_fake_io_off + wo;
+	phys_writeb(phys+wo+0x00,(Bit8u)0xEF);	/* OUT DX,AX */
+	phys_writeb(phys+wo+0x01,(Bit8u)0xCB);	/* RETF */
+	wo += 2;
+
+	vm86_fake_io_offs[5] = vm86_fake_io_off + wo;
+	phys_writeb(phys+wo+0x00,(Bit8u)0x66);	/* OUT DX,EAX */
+	phys_writeb(phys+wo+0x01,(Bit8u)0xEF);
+	phys_writeb(phys+wo+0x02,(Bit8u)0xCB);	/* RETF */
+	wo += 3;
+}
 
 Bitu CPU_ForceV86FakeIO_In(Bitu port,Bitu len) {
 	static const char suffix[4] = {'B','W','?','D'};
-	Bitu phys = (vm86_fake_io_seg << 4) + vm86_fake_io_off;
 	Bitu old_ax,old_dx,ret;
 
-	/* argh */
-	CPU_Core_Dyn_X86_Cache_Reset();
+	init_vm86_fake_io();
 
 	/* save EAX:EDX and setup DX for IN instruction */
 	old_ax = reg_eax;
@@ -2593,29 +2636,12 @@ Bitu CPU_ForceV86FakeIO_In(Bitu port,Bitu len) {
 
 	reg_edx = port;
 
-	if (len == 1) {
-		phys_writeb(phys+0x00,(Bit8u)0xEC);	/* IN AL,DX */
-		phys_writeb(phys+0x01,(Bit8u)0xCB);	/* RETF */
-	}
-	else if (len == 2) {
-		phys_writeb(phys+0x00,(Bit8u)0xED);	/* IN AX,DX */
-		phys_writeb(phys+0x01,(Bit8u)0xCB);	/* RETF */
-	}
-	else if (len == 4) {
-		phys_writeb(phys+0x00,(Bit8u)0x66);	/* IN EAX,DX */
-		phys_writeb(phys+0x01,(Bit8u)0xED);
-		phys_writeb(phys+0x02,(Bit8u)0xCB);	/* RETF */
-	}
-	else {
-		abort();
-	}
-
 	/* DEBUG */
 	fprintf(stderr,"CPU virtual 8086 mode: Forcing CPU to execute 'IN%c 0x%04x so OS can trap it. ",suffix[len-1],port);
 	fflush(stderr);
 
 	/* make the CPU execute that instruction */
-	CALLBACK_RunRealFar(vm86_fake_io_seg,vm86_fake_io_off);
+	CALLBACK_RunRealFar(vm86_fake_io_seg,vm86_fake_io_offs[(len==4?2:(len-1))+0]);
 
 	/* take whatever the CPU or OS v86 trap left in EAX and return it */
 	ret = reg_eax;
@@ -2632,11 +2658,9 @@ Bitu CPU_ForceV86FakeIO_In(Bitu port,Bitu len) {
 
 void CPU_ForceV86FakeIO_Out(Bitu port,Bitu val,Bitu len) {
 	static const char suffix[4] = {'B','W','?','D'};
-	Bitu phys = (vm86_fake_io_seg << 4) + vm86_fake_io_off;
 	Bitu old_ax,old_dx;
 
-	/* argh */
-	CPU_Core_Dyn_X86_Cache_Reset();
+	init_vm86_fake_io();
 
 	/* save EAX:EDX and setup DX/AX for OUT instruction */
 	old_ax = reg_eax;
@@ -2645,28 +2669,11 @@ void CPU_ForceV86FakeIO_Out(Bitu port,Bitu val,Bitu len) {
 	reg_edx = port;
 	reg_eax = val;
 
-	if (len == 1) {
-		phys_writeb(phys+0x00,(Bit8u)0xEE);	/* OUT DX,AL */
-		phys_writeb(phys+0x01,(Bit8u)0xCB);	/* RETF */
-	}
-	else if (len == 2) {
-		phys_writeb(phys+0x00,(Bit8u)0xEF);	/* OUT DX,AX */
-		phys_writeb(phys+0x01,(Bit8u)0xCB);	/* RETF */
-	}
-	else if (len == 4) {
-		phys_writeb(phys+0x00,(Bit8u)0x66);	/* OUT DX,EAX */
-		phys_writeb(phys+0x01,(Bit8u)0xEF);
-		phys_writeb(phys+0x02,(Bit8u)0xCB);	/* RETF */
-	}
-	else {
-		abort();
-	}
-
 	/* DEBUG */
 	fprintf(stderr,"CPU virtual 8086 mode: Forcing CPU to execute 'OUT%c 0x%04x,0x%02x so OS can trap it.\n",suffix[len-1],port,val);
 
 	/* make the CPU execute that instruction */
-	CALLBACK_RunRealFar(vm86_fake_io_seg,vm86_fake_io_off);
+	CALLBACK_RunRealFar(vm86_fake_io_seg,vm86_fake_io_offs[(len==4?2:(len-1))+3]);
 
 	/* then restore EAX:EDX */
 	reg_eax = old_ax;