zasm: have a whole kernel in emulation instead of a simple wrapper

zasm is going to need to call to kernel code...

apps/zasm/emul/.gitignore

@@ -1,4 +1,4 @@
 libz80
-wrapper.h
+kernel.h
 zasm.h
 zasm

apps/zasm/emul/Makefile

@@ -1,11 +1,11 @@
-zasm: zasm.c libz80/libz80.so wrapper.h zasm.h
+zasm: zasm.c libz80/libz80.so kernel.h zasm.h
 	cc $< -l z80 -L./libz80 -Wl,-rpath ./libz80 -o $@
 
 libz80/libz80.so: libz80/Makefile
 	make -C libz80
 
-wrapper.h: wrapper.asm
-	scas -o - $< | ./bin2c.sh WRAPPER > $@
+kernel.h: glue.asm
+	scas -o - $< | ./bin2c.sh KERNEL > $@
 
 zasm.h: ../zasm.asm
 	scas -o - $< | ./bin2c.sh ZASM > $@

apps/zasm/emul/glue.asm

@@ -0,0 +1,22 @@
+; Glue code for the emulated environment
+RAMSTART	.equ	0x8000
+RAMEND		.equ	0xffff
+ZASM_CODE	.equ	RAMSTART
+ZASM_INPUT	.equ	0xa000
+ZASM_OUTPUT	.equ	0xd000
+
+jr	init
+init:
+	di
+	ld	hl, RAMEND
+	ld	sp, hl
+	ld	hl, ZASM_INPUT
+	ld	de, ZASM_OUTPUT
+	call	ZASM_CODE
+	; signal the emulator we're done
+	; BC contains the number of written bytes
+	ld	a, b
+	out	(c), a
+	halt
+
+#include "core.asm"

apps/zasm/emul/wrapper.asm

@@ -1,15 +0,0 @@
-; setup the stack
-ld	hl, 0xffff
-ld	sp, hl
-; zasm input
-ld	hl, 0x9000
-; zasm output
-ld	de, 0xc000
-call	zasm
-; signal the emulator we're done
-; BC contains the number of written bytes
-ld	a, b
-out	(c), a
-halt
-zasm:
-; beginning of the code

apps/zasm/emul/zasm.c

@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include "libz80/z80.h"
-#include "wrapper.h"
+#include "kernel.h"
 #include "zasm.h"
 
 /* zasm is a "pure memory" application. It starts up being told memory location
@@ -12,9 +12,10 @@
  * spit the contents of the dest memory to stdout.
  */
 
-// in sync with wrapper.asm
-#define READFROM 0x9000
-#define WRITETO 0xc000
+// in sync with glue.asm
+#define READFROM 0xa000
+#define WRITETO 0xd000
+#define ZASM_CODE_OFFSET 0x8000
 
 static Z80Context cpu;
 static uint8_t mem[0xffff];
@@ -48,13 +49,11 @@ static void mem_write(int unused, uint16_t addr, uint8_t val)
 int main()
 {
     // initialize memory
-    int wrapperlen = sizeof(WRAPPER);
-    for (int i=0; i<wrapperlen; i++) {
-        mem[i] = WRAPPER[i];
+    for (int i=0; i<sizeof(KERNEL); i++) {
+        mem[i] = KERNEL[i];
     }
-    int zasm = sizeof(ZASM);
-    for (int i=0; i<zasm; i++) {
-        mem[i+wrapperlen] = ZASM[i];
+    for (int i=0; i<sizeof(ZASM); i++) {
+        mem[i+ZASM_CODE_OFFSET] = ZASM[i];
     }
     int ptr = READFROM;
     int c = getchar();