1 files changed, 102 insertions, 0 deletions
diff --git a/vm.c b/vm.c
new file mode 100644
index 0000000..00692b0
--- /dev/null
+++ b/vm.c
@@ -0,0 +1,102 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "val.h"
+#include "vm.h"
+
+void *M(void *p, size_t sz) {
+	if (sz == 0) {
+		free(p);
+		return NULL;
+	} else {
+		return realloc(p, sz);
+	}
+}
+
+
+Chunk chunk_new() {
+	return (Chunk){
+		.blen = 0, .bcap = 0, .b = NULL,
+		.clen = 0, .ccap = 0, .c = NULL,
+	};
+}
+size_t chunk_wbc(Chunk *ch, uint8_t byte) {
+	if (ch->blen == ch->bcap) {
+		size_t newsz = (ch->bcap == 0 ? 8 : ch->bcap * 2);
+		ch->b = M(ch->b, newsz * sizeof(uint8_t));
+		ch->bcap = newsz;
+	}
+	size_t ix = ch->blen;
+	ch->b[ix] = byte;
+	ch->blen ++;
+	return ix;
+}
+size_t chunk_wconst(Chunk *ch, Val v) {
+	if (ch->clen == ch->ccap) {
+		size_t newsz = (ch->ccap == 0 ? 8 : ch->ccap *2);
+		ch->c = M(ch->c, newsz * sizeof(Val));
+		ch->ccap = newsz;
+	}
+	size_t ix = ch->clen;
+	ch->c[ix] = v;
+	ch->clen ++;
+	return ix;
+}
+
+Vm vm_new(Chunk *ch) {
+	Vm vm = (Vm){ 
+		.ch = ch,
+		.ip = 0,
+		.sp = 0
+	};
+	for (int i = 0; i < STACKSIZE; i++) {
+		vm.stack[i] = VAL_NIL;
+	}
+	return vm;
+}
+
+
+static void runvm() {
+	Chunk ch = chunk_new();
+	chunk_wbc(&ch, OP_LOADK);
+	chunk_wbc(&ch, 1);
+	chunk_wbc(&ch, OP_PRINT);
+	chunk_wbc(&ch, OP_LOADK);
+	chunk_wbc(&ch, 2);
+	chunk_wbc(&ch, OP_LOADK);
+	chunk_wbc(&ch, 0);
+	chunk_wbc(&ch, OP_RET);
+
+	chunk_wconst(&ch, VAL_BOOL(false));
+	chunk_wconst(&ch, VAL_NIL);
+	chunk_wconst(&ch, VAL_NUM(420.69));
+
+	Vm vm = vm_new(&ch);
+#define RBYTE() (vm.ch->b[vm.ip++])
+
+	while (1) {
+		uint8_t instr = RBYTE();
+		switch (instr) {
+		case OP_RET:
+			printf("done!\n");
+			goto done;
+			break;
+		case OP_LOADK:
+			uint8_t cix = RBYTE();
+			Val v = vm.ch->c[cix];
+			print_val(v);
+			break;
+		case OP_PRINT:
+			printf("print\n");
+			break;
+		}
+	}
+	done:;
+}
+
+int main() { runvm(); }
+
+