From 8c3037662ba572a6935170dbd4cb8cc8a3636417 Mon Sep 17 00:00:00 2001
From: ubq323 <ubq323@ubq323.website>
Date: Sat, 22 Jun 2024 18:22:24 +0100
Subject: compilation of functions, and some parts of interpreting them

---
 vm.c | 41 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 37 insertions(+), 4 deletions(-)

(limited to 'vm.c')

diff --git a/vm.c b/vm.c
index 3410e1c..4e412c1 100644
--- a/vm.c
+++ b/vm.c
@@ -41,12 +41,13 @@ int runvm(State *S) {
 #define PEEK()  (th->stack[th->sp-1])
 
 	while (1) {
+		ch = th->ch;
+		if (S->do_trace) {
+			printf("%p ",(void *)ch);
+			disasm_instr(ch, th->ip);
+		}
 		uint8_t instr = RBYTE();
 		switch (instr) {
-		case OP_RET:
-			status  = 0;
-			goto done;
-			break;
 		case OP_LOADK: {
 			uint8_t cix = RBYTE();
 			Val v = ch->consts.d[cix];
@@ -155,7 +156,39 @@ int runvm(State *S) {
 		case OP_TRUE: PUSH(VAL_TRUE); break;
 		case OP_FALSE: PUSH(VAL_FALSE); break;
 
+		case OP_CALL: {
+			uint8_t len = RBYTE();
+			// ignore arguments for now
+			th->sp -= len-1;
+			Val callee = POP();
+			if (!IS_FUNC(callee)) {
+				fprintf(stderr, "can only call functions\n");
+				goto done;
+			}
+			ObjFunc *func = AS_FUNC(callee);
+
+			StackFrame *sf = &th->rstack[th->rsp++];
+			sf->ch = th->ch;
+			sf->ip = th->ip;
+
+			th->ch = &func->ch;
+			th->ip = 0;
 		}
+		break;
+
+		case OP_RET: {
+			StackFrame *sf = &th->rstack[--th->rsp]; 
+			th->ch = sf->ch;
+			th->ip = sf->ip;
+			break;
+		}
+		case OP_HALT:
+			status = 0;
+			goto done;
+			break;
+
+		}
+
 	}
 	done:;
 	return status;
-- 
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