Complete the assembler

3 files changed, 178 insertions, 8 deletions

diff --git a/src/c8asm/assembler.c b/src/c8asm/assembler.c
index 0d02555..6cdebe7 100644
--- a/src/c8asm/assembler.c
+++ b/src/c8asm/assembler.c
@@ -1,3 +1,4 @@
+#include <arpa/inet.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -16,7 +17,8 @@
 #	define unreachable() __builtin_unreachable()
 #endif
 
-#define E_LEXISTS "label ‘%.*s’ has already been declared"
+#define E_LEXISTS  "label ‘%.*s’ has already been declared"
+#define E_LNEXISTS "label ‘%.*s’ hasn’t been declared"
 
 struct label {
 	uint16_t addr;
@@ -30,8 +32,11 @@ struct labels {
 
 static bool u8eq(struct u8view, struct u8view);
 static void pushlabel(struct labels *, struct label);
+static uint16_t getaddr(struct raw_addr);
+static struct label *getlabel(struct u8view);
 
 static size_t i;
+static struct labels locals, globals;
 
 bool
 u8eq(struct u8view x, struct u8view y)
@@ -39,6 +44,29 @@ u8eq(struct u8view x, struct u8view y)
 	return x.len == y.len && memcmp(x.p, y.p, x.len) == 0;
 }
 
+struct label *
+getlabel(struct u8view sv)
+{
+	struct labels *xs = sv.p[0] == '.' ? &locals : &globals;
+	da_foreach (xs, x) {
+		if (u8eq(x->sv, sv))
+			return x;
+	}
+	return nullptr;
+}
+
+uint16_t
+getaddr(struct raw_addr a)
+{
+	if (a.label) {
+		struct label *lbl = getlabel(a.sv);
+		if (lbl)
+			return lbl->addr;
+		die_with_off(filename, a.sv.p - baseptr, E_LNEXISTS, U8_PRI_ARGS(a.sv));
+	}
+	return a.val;
+}
+
 void
 pushlabel(struct labels *dst, struct label lbl)
 {
@@ -55,7 +83,11 @@ pushlabel(struct labels *dst, struct label lbl)
 void
 assemble([[maybe_unused]] FILE *stream, struct ast ast)
 {
-	static struct labels locals, globals;
+#define PUT(X) \
+	do { \
+		uint16_t __x = htons(X); \
+		fwrite(&__x, 1, sizeof(__x), stream); \
+	} while (false)
 
 	da_foreach (&ast, node) {
 		if (node->kind == D_LABEL) {
@@ -70,5 +102,143 @@ assemble([[maybe_unused]] FILE *stream, struct ast ast)
 			unreachable();
 	}
 
+	da_foreach (&ast, node) {
+		if (node->kind == D_LABEL)
+			continue;
+		if (node->kind != D_INSTR)
+			unreachable();
+
+		switch (node->instr.kind) {
+		case I_ADD_I_VX:
+			PUT(0xF01E | (node->instr.args[0].val << 8));
+			break;
+		case I_ADD_VX_B:
+			PUT(0x7000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val);
+			break;
+		case I_ADD_VX_VY:
+			PUT(0x8004 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_AND:
+			PUT(0x8002 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_BCD:
+			PUT(0xF033 | (node->instr.args[0].val << 8));
+			break;
+		case I_CALL:
+			PUT(0x2000 | getaddr(node->instr.args[0]));
+			break;
+		case I_CLS:
+			PUT(0x00E0);
+			break;
+		case I_DB:
+			da_foreach (&node->instr, byte)
+				fputc(*byte, stream);
+			break;
+		case I_DRW:
+			PUT(0xD000 | (node->instr.args[0].val << 8)
+			    | (node->instr.args[1].val << 4) | node->instr.args[2].val);
+			break;
+		case I_HEX:
+			PUT(0xF029 | (node->instr.args[0].val << 8));
+			break;
+		case I_JP_A:
+			PUT(0x1000 | getaddr(node->instr.args[0]));
+			break;
+		case I_JP_V0_A:
+			PUT(0xB000 | getaddr(node->instr.args[0]));
+			break;
+		case I_LD_DT:
+			PUT(0xF015 | (node->instr.args[0].val << 8));
+			break;
+		case I_LD_I:
+			PUT(0xA000 | getaddr(node->instr.args[0]));
+			break;
+		case I_LD_ST:
+			PUT(0xF018 | (node->instr.args[0].val << 8));
+			break;
+		case I_LD_VX_B:
+			PUT(0x6000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val);
+			break;
+		case I_LD_VX_DT:
+			PUT(0xF007 | (node->instr.args[0].val << 8));
+			break;
+		case I_LD_VX_K:
+			PUT(0xF00A | (node->instr.args[0].val << 8));
+			break;
+		case I_LD_VX_VY:
+			PUT(0x8000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_OR:
+			PUT(0x8001 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_RET:
+			PUT(0x00EE);
+			break;
+		case I_RND:
+			PUT(0xC000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val);
+			break;
+		case I_RSTR:
+			PUT(0xF065 | (node->instr.args[0].val << 8));
+			break;
+		case I_SE_VX_B:
+			PUT(0x3000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val);
+			break;
+		case I_SE_VX_VY:
+			PUT(0x5000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_SHL:
+			PUT(0x800E | (node->instr.args[0].val << 8));
+			break;
+		case I_SHR:
+			PUT(0x8006 | (node->instr.args[0].val << 8));
+			break;
+		case I_SKNP:
+			PUT(0xE0A1 | (node->instr.args[0].val << 8));
+			break;
+		case I_SKP:
+			PUT(0xE09E | (node->instr.args[0].val << 8));
+			break;
+		case I_SNE_VX_B:
+			PUT(0x4000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val);
+			break;
+		case I_SNE_VX_VY:
+			PUT(0x9000 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_STOR:
+			PUT(0xF055 | (node->instr.args[0].val << 8));
+			break;
+		case I_SUB:
+			PUT(0x8005 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_SUBN:
+			PUT(0x8007 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		case I_SYS:
+			PUT(getaddr(node->instr.args[0]));
+			break;
+		case I_XOR:
+			PUT(0x8003 | (node->instr.args[0].val << 8)
+			    | node->instr.args[1].val << 4);
+			break;
+		default:
+			unreachable();
+		}
+	}
+
 	locals.len = 0;
+
+#undef PUT
 }
diff --git a/src/c8asm/parser.c b/src/c8asm/parser.c
index b746bea..03d190d 100644
--- a/src/c8asm/parser.c
+++ b/src/c8asm/parser.c
@@ -383,10 +383,10 @@ parseop_jp(void)
 	if (op.kind == T_IDENT)
 		rt = regtype(op.sv);
 	if (op.kind == T_NUMBER || (op.kind == T_IDENT && rt == RT_NONE)) {
-		ins.kind = I_JP_ADDR;
+		ins.kind = I_JP_A;
 		ins.args[ins.len++] = parseaddr(op);
 	} else if (op.kind == T_IDENT) {
-		ins.kind = I_JP_V0_ADDR;
+		ins.kind = I_JP_V0_A;
 		if (op.sv.len != 2 || !memeq(op.sv.p, "v0", 2)) {
 			die_with_off(op.sv.p, E_EXPECTED, "v0-register or address",
 			             tokrepr(op.kind), U8_PRI_ARGS(op.sv));
@@ -447,7 +447,7 @@ parseop_ld(void)
 
 			break;
 		case T_NUMBER:
-			ins.kind = I_LD_VX_BYTE;
+			ins.kind = I_LD_VX_B;
 			ins.args[ins.len++].val = parsenum(op, NS_BYTE);
 			break;
 		default:
diff --git a/src/c8asm/parser.h b/src/c8asm/parser.h
index 392b003..a8cc03c 100644
--- a/src/c8asm/parser.h
+++ b/src/c8asm/parser.h
@@ -19,12 +19,12 @@ typedef enum {
 	I_DB,
 	I_DRW,
 	I_HEX,
-	I_JP_ADDR,
-	I_JP_V0_ADDR,
+	I_JP_A,
+	I_JP_V0_A,
 	I_LD_DT,
 	I_LD_I,
 	I_LD_ST,
-	I_LD_VX_BYTE,
+	I_LD_VX_B,
 	I_LD_VX_DT,
 	I_LD_VX_K,
 	I_LD_VX_VY,