From a4bfe11eee81d38c7b6840bc7b886210f8ca3e90 Mon Sep 17 00:00:00 2001
From: Steven Hugg <hugg@fasterlight.com>
Date: Thu, 9 Jan 2020 20:24:29 -0600
Subject: [PATCH] added tools/sim6502, msx skeleton files

---
 presets/msx/skeleton.sdcc |  20 +++++++
 presets/msx/skeleton.zmac |  33 +++++++++++
 src/tools/sim6502.ts      | 121 ++++++++++++++++++++++++++++++++++++++
 tsconfig.json             |   3 +
 4 files changed, 177 insertions(+)
 create mode 100644 presets/msx/skeleton.sdcc
 create mode 100644 presets/msx/skeleton.zmac
 create mode 100644 src/tools/sim6502.ts

diff --git a/presets/msx/skeleton.sdcc b/presets/msx/skeleton.sdcc
new file mode 100644
index 00000000..1a515ab6
--- /dev/null
+++ b/presets/msx/skeleton.sdcc
@@ -0,0 +1,20 @@
+
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "msxbios.h"
+//#link "msxbios.c"
+
+void main()
+{
+  int counter=0;
+  
+  INITXT();
+  SCNCNT = 1; // set keyboard scan counter
+ 
+  while (1) {
+    counter++;
+    printf("Hello, World!    %04x\n", counter++);
+  }
+}
diff --git a/presets/msx/skeleton.zmac b/presets/msx/skeleton.zmac
new file mode 100644
index 00000000..21d727ae
--- /dev/null
+++ b/presets/msx/skeleton.zmac
@@ -0,0 +1,33 @@
+
+; Hello World example
+
+; ROM routine for character output
+CHPUT:  equ $00A2
+
+	org 0x4000
+        
+; MSX cartridge header @ 0x4000 - 0x400f
+	dw 0x4241
+        dw Init
+        dw Init
+        dw 0
+        dw 0
+        dw 0
+        dw 0
+        dw 0
+
+; initialize and print message
+Init:
+    ld hl, msg
+    call puts
+    jp Init	; loop forever
+puts:               ; print 0-terminated string in HL
+    ld a,(hl)
+    or a
+    ret z
+    call CHPUT      ; displays one character in A
+    inc hl
+    jr puts
+
+; ASCII message + CR LF
+msg:    defm "Hello, world!",13,10,0
diff --git a/src/tools/sim6502.ts b/src/tools/sim6502.ts
new file mode 100644
index 00000000..e232fa32
--- /dev/null
+++ b/src/tools/sim6502.ts
@@ -0,0 +1,121 @@
+
+import { MOS6502 } from "../common/cpu/MOS6502";
+import { disassemble6502 } from "../common/cpu/disasm6502";
+import { Bus } from "../common/devices";
+import { hex, rpad } from "../common/util";
+
+class CPUSimulator implements Bus {
+
+    cpu : MOS6502;
+    ram : Uint8Array;
+    ok = false;
+    linebuf = '';
+
+    constructor() {
+        this.cpu = new MOS6502();
+        this.ram = new Uint8Array(0x10000);
+        this.cpu.connectMemoryBus(this);
+    }
+
+    loadROM(rom: Uint8Array) {
+        var hdrlen = 0;
+        var prgstart = 0x200;
+        if (rom[0] == 0x00) hdrlen = 0;
+        else if (rom[0] == 0x73 && rom[1] == 0x69) hdrlen = 12;
+        else throw Error("Bad header " + rom[0]);
+        this.ram.set(rom.slice(hdrlen), prgstart);
+        this.ram[0xfff4] = 0x60; // RTS
+        this.ram[0xfff5] = 0x60; // RTS
+        this.ram[0xfff6] = 0x60; // RTS
+        this.ram[0xfff7] = 0x60; // RTS
+        this.ram[0xfff8] = 0x60; // RTS
+        this.ram[0xfffc] = (prgstart & 0xff);
+        this.ram[0xfffd] = ((prgstart >> 8) & 0xff);
+        this.cpu.reset();
+        this.ok = true;
+    }
+
+    read(a: number): number {
+        return this.ram[a] & 0xff;
+    }
+    write(a: number, v: number): void {
+        if (a >= 0x200 && a <= 0xbfff) {
+            this.warn("Write in code area: " + hex(a,4))
+        }
+        if (a >= 0x100 && a < (this.cpu.getSP()|0x100)) {
+            this.warn("Write outside stack area: " + hex(a,4))
+        }
+        this.ram[a] = v;
+    }
+    readConst?(a: number): number {
+        return this.ram[a] & 0xff;
+    }
+
+    tick() {
+        this.cpu.advanceInsn();
+        this.log();
+    }
+
+    warn(s:string) {
+        console.log("###",hex(this.cpu.getPC(),4),s);
+    }
+
+    log() {
+        var st = this.cpu.saveState();
+        var pc = this.cpu.getPC();
+        var b0 = this.readConst(pc);
+        var b1 = this.readConst(pc+1);
+        var b2 = this.readConst(pc+2);
+        var line = disassemble6502(pc, b0, b1, b2);
+        var stack = "";
+        for (var i=0xff; i>st.SP-0; i--) {
+            stack += hex(this.readConst(i+0x100),2);
+            //if (i==st.SP) stack += " ";
+        }
+        console.log(
+            hex(pc,4),
+            rpad(line.line, 30),
+            hex(st.A), hex(st.X), hex(st.Y), hex(st.SP),
+            st.C?"C":"-", st.N?"N":"-", st.Z?"Z":"-", st.V?"V":"-",
+            stack);
+        if (pc == 0xfff7) {
+            let addr = this.readStackArg(0);
+            let s = '';
+            for (var i=0; i<this.readStackArg(2); i++) {
+                let cc = this.readConst(addr+i);
+                s += String.fromCharCode(cc);
+                this.linebuf += s;
+                if (cc == 10 || cc == 13) {
+                    console.log("---LINE", this.linebuf);
+                    this.linebuf = '';
+                }
+            }
+            console.log("---WRITE", s, st.A, hex(addr), this.readStackArg(2));
+        }
+        else if (pc == 0xfff9) {
+            console.log("---EXIT", st.A);
+            this.ok = false;
+        }
+        else if (b0 == 0x00 || line.line == 'KIL') {
+            this.ok = false;
+        }
+        else if (b0 == 0x20 || b0 == 0x60) {
+            console.log();
+        }
+    }
+
+    readStackArg(offset: number) : number {
+        var a = (this.cpu.getSP() | 0x100) + offset + 3;
+        return this.readConst(a) + this.readConst(a+1) * 256;
+    }
+}
+
+const fs = require('fs');
+const rom = fs.readFileSync(process.argv[2], null);
+console.log(rom);
+
+var sim = new CPUSimulator();
+sim.loadROM(rom);
+while (sim.ok) {
+    sim.tick();
+}
diff --git a/tsconfig.json b/tsconfig.json
index 22fd193b..ef679cd3 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -15,6 +15,9 @@
     },
     {
       "path": "./src/worker"
+    },
+    {
+      "path": "./src/tools"
     }
   ]
 }