emul/8086: add INT hooks

emul/8086/.gitignore

@@ -0,0 +1,2 @@
+/forth
+/forth.bin

emul/8086/Makefile

@@ -7,14 +7,16 @@ BLKFS = $(CDIR)/blkfs
 .PHONY: all
 all: $(TARGETS)
 
-forth: forth.c $(OBJS)
-	$(CC) forth.c $(OBJS) -lncurses -o $@
+forth: forth.c forth.bin $(OBJS)
+	$(CC) -DFBIN_PATH=\"`pwd`/forth.bin\" forth.c $(OBJS) -lncurses -o $@
 
-emul.o: emul.c forth.bin $(BLKFS)
+emul.o: emul.c $(BLKFS)
 	$(CC) -DFBIN_PATH=\"`pwd`/forth.bin\" -DBLKFS_PATH=\"`pwd`/$(BLKFS)\" -c -o emul.o emul.c
 
-forth.bin: xcomp.fs $(STAGE) $(BLKFS)
-	$(CDIR)/stage < xcomp.fs > $@
+forth.bin: foo.asm
+	nasm -o $@ foo.asm
+#forth.bin: xcomp.fs $(STAGE) $(BLKFS)
+#	$(CDIR)/stage < xcomp.fs > $@
 
 $(BLKFS): $(STAGE)
 

emul/8086/cpu.c

@@ -22,6 +22,7 @@
 
 #include <stdint.h>
 #include <stdio.h>
+#include "cpu.h"
 
 // Defines below are from config.h
 //be sure to only define ONE of the CPU_* options at any given time, or
@@ -49,58 +50,11 @@
 	#define CPU_SET_HIGH_FLAGS
 #endif
 
-#define regax 0
-#define regcx 1
-#define regdx 2
-#define regbx 3
-#define regsp 4
-#define regbp 5
-#define regsi 6
-#define regdi 7
-#define reges 0
-#define regcs 1
-#define regss 2
-#define regds 3
-
-#ifdef __BIG_ENDIAN__
-#define regal 1
-#define regah 0
-#define regcl 3
-#define regch 2
-#define regdl 5
-#define regdh 4
-#define regbl 7
-#define regbh 6
-#else
-#define regal 0
-#define regah 1
-#define regcl 2
-#define regch 3
-#define regdl 4
-#define regdh 5
-#define regbl 6
-#define regbh 7
-#endif
-
-union _bytewordregs_ {
-	uint16_t wordregs[8];
-	uint8_t byteregs[8];
-};
-
 #define StepIP(x)	ip += x
-#define getmem8(x, y)	read86(segbase(x) + y)
-#define getmem16(x, y)	readw86(segbase(x) + y)
-#define putmem8(x, y, z)	write86(segbase(x) + y, z)
-#define putmem16(x, y, z)	writew86(segbase(x) + y, z)
 #define signext(value)	(int16_t)(int8_t)(value)
 #define signext32(value)	(int32_t)(int16_t)(value)
-#define getreg16(regid)	regs.wordregs[regid]
-#define getreg8(regid)	regs.byteregs[byteregtable[regid]]
-#define putreg16(regid, writeval)	regs.wordregs[regid] = writeval
-#define putreg8(regid, writeval)	regs.byteregs[byteregtable[regid]] = writeval
 #define getsegreg(regid)	segregs[regid]
 #define putsegreg(regid, writeval)	segregs[regid] = writeval
-#define segbase(x)	((uint32_t) x << 4)
 
 #define makeflagsword() \
 	( \
@@ -174,6 +128,7 @@ static const uint8_t parity[0x100] = {
 };
 
 uint8_t	RAM[0x100000];
+INTHOOK INTHOOKS[0x100] = {0};
 uint8_t	opcode, segoverride, reptype, hltstate = 0;
 uint16_t segregs[4], savecs, saveip, ip, useseg, oldsp;
 uint8_t	tempcf, oldcf, cf, pf, af, zf, sf, tf, ifl, df, of, mode, reg, rm;
@@ -186,29 +141,29 @@ union _bytewordregs_ regs;
 
 uint8_t	portram[0x10000];
 
-void intcall86 (uint8_t intnum);
+void intcall86(uint8_t intnum);
 
 static void	portout (uint16_t portnum, uint8_t value) {}
 static void	portout16 (uint16_t portnum, uint16_t value) {}
 static uint8_t	portin (uint16_t portnum) { return 0; }
 static uint16_t portin16 (uint16_t portnum) { return 0; }
 
-static void write86 (uint32_t addr32, uint8_t value) {
+void write86 (uint32_t addr32, uint8_t value) {
 	tempaddr32 = addr32 & 0xFFFFF;
     RAM[tempaddr32] = value;
 }
 
-static void writew86 (uint32_t addr32, uint16_t value) {
-	write86 (addr32, (uint8_t) value);
-	write86 (addr32 + 1, (uint8_t) (value >> 8) );
+void writew86 (uint32_t addr32, uint16_t value) {
+	write86(addr32, (uint8_t) value);
+	write86(addr32 + 1, (uint8_t) (value >> 8) );
 }
 
-static uint8_t read86 (uint32_t addr32) {
+uint8_t read86 (uint32_t addr32) {
 	addr32 &= 0xFFFFF;
 	return (RAM[addr32]);
 }
 
-static uint16_t readw86 (uint32_t addr32) {
+uint16_t readw86 (uint32_t addr32) {
 	return ( (uint16_t) read86 (addr32) | (uint16_t) (read86 (addr32 + 1) << 8) );
 }
 
@@ -1242,9 +1197,17 @@ static void op_grp5() {
 		}
 }
 
-void intcall86 (uint8_t intnum) {
+void intcall86(uint8_t intnum) {
+    if (intnum == 0) {
+        fprintf(stderr, "INT 0 called, halting\n");
+        hltstate = 1;
+        return;
+    }
+    if (INTHOOKS[intnum] != NULL) {
+        INTHOOKS[intnum]();
+        return;
+    }
     fprintf(stderr, "Unknown INT called: %x\n", intnum);
-    hltstate = 1;
 	/*push (makeflagsword() );
 	push (segregs[regcs]);
 	push (ip);
@@ -3437,8 +3400,3 @@ void reset86() {
 	ip = 0;
 	hltstate = 0;
 }
-
-void printregs() {
-    fprintf(stderr, "AL: %x\n", getreg8(regal));
-}
-

emul/8086/cpu.h

@@ -1,3 +1,57 @@
+#pragma once
+#define regax 0
+#define regcx 1
+#define regdx 2
+#define regbx 3
+#define regsp 4
+#define regbp 5
+#define regsi 6
+#define regdi 7
+#define reges 0
+#define regcs 1
+#define regss 2
+#define regds 3
+
+#ifdef __BIG_ENDIAN__
+#define regal 1
+#define regah 0
+#define regcl 3
+#define regch 2
+#define regdl 5
+#define regdh 4
+#define regbl 7
+#define regbh 6
+#else
+#define regal 0
+#define regah 1
+#define regcl 2
+#define regch 3
+#define regdl 4
+#define regdh 5
+#define regbl 6
+#define regbh 7
+#endif
+
+#define segbase(x)	((uint32_t) x << 4)
+#define getmem8(x, y)	read86(segbase(x) + y)
+#define getmem16(x, y)	readw86(segbase(x) + y)
+#define putmem8(x, y, z)	write86(segbase(x) + y, z)
+#define putmem16(x, y, z)	writew86(segbase(x) + y, z)
+#define getreg16(regid)	regs.wordregs[regid]
+#define getreg8(regid)	regs.byteregs[byteregtable[regid]]
+#define putreg16(regid, writeval)	regs.wordregs[regid] = writeval
+#define putreg8(regid, writeval)	regs.byteregs[byteregtable[regid]] = writeval
+
+typedef void (*INTHOOK) ();
+union _bytewordregs_ {
+	uint16_t wordregs[8];
+	uint8_t byteregs[8];
+};
+
+
+void write86 (uint32_t addr32, uint8_t value);
+void writew86 (uint32_t addr32, uint16_t value);
+uint8_t read86 (uint32_t addr32);
+uint16_t readw86 (uint32_t addr32);
 void exec86(int execloops);
 void reset86();
-void printregs();

emul/8086/foo.asm

@@ -0,0 +1,3 @@
+mov al, 'X'
+int 1
+hlt

emul/8086/forth.c

@@ -2,21 +2,40 @@
 #include <stdio.h>
 #include "cpu.h"
 
-extern uint8_t	RAM[0x100000];
+#ifndef FBIN_PATH
+#error FBIN_PATH needed
+#endif
+
+extern uint8_t byteregtable[8];
+extern union _bytewordregs_ regs;
+extern INTHOOK INTHOOKS[0x100];
+
+/* we have a fake INT API:
+INT 1: EMIT. AL = char to spit
+INT 2: KEY. AL = char read
+*/
+
+void int1() {
+    putchar(getreg8(regal));
+}
 
 int main(int argc, char *argv[])
 {
-    int i = 0;
-    int ch = 0;
-
+    INTHOOKS[1] = int1;
     reset86();
-    ch = getchar();
-    while (ch != EOF) {
-        RAM[i++] = ch;
-        ch = getchar();
+    // initialize memory
+    FILE *bfp = fopen(FBIN_PATH, "r");
+    if (!bfp) {
+        fprintf(stderr, "Can't open forth.bin\n");
+        return 1;
+    }
+    int i = 0;
+    int c = getc(bfp);
+    while (c != EOF) {
+        write86(i++, c);
+        c = getc(bfp);
     }
-    printregs();
-    exec86(1);
-    printregs();
+    fclose(bfp);
+    exec86(100);
     return 0;
 }