From 889e34d0ca986f03de77dfa383c12f4980e746ee Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Wed, 3 Nov 2021 14:51:42 +0100
Subject: Fix behaviour of logic comparisons

---
 src/compiler.h | 96 +++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 55 insertions(+), 41 deletions(-)

diff --git a/src/compiler.h b/src/compiler.h
index 441b665..e511b7c 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -26,10 +26,11 @@ generate_label(void) {
     // for freeing the memory.
     static size_t label_counter = 0;
     char buf[32];
-    memset(buf, 0, 32);
     sprintf(buf, ".BDLL%ld", label_counter++);
-    char * ret = malloc(strlen(buf));
-    memcpy(ret, buf, strlen(buf));
+    size_t len = strlen(buf);
+    char * ret = malloc(len + 1);
+    memcpy(ret, buf, len);
+    ret[len] = 0;
     return ret;
 }
 
@@ -85,9 +86,6 @@ typedef enum OpType {
     OP_IS_BOOL,
     OP_IS_FIXNUM,
     // Logic operations.
-    OP_NOT,
-    OP_AND,
-    OP_OR,
     OP_EQUAL,
     OP_GREATER,
     OP_LESS,
@@ -126,49 +124,65 @@ compile_type_predicate(OpType op, Object* args) {
 }
 
 void
-compile_logic_list(OpType op, Object* args) {
-    printf("    ;; --> compile_logic_list\n");
+compile_not(Object* args) {
+    printf("    ;; --> compile_not\n");
     compile_object(args->head);
-    if (op == OP_NOT) {
+    printf("    pop     rax\n");
+    printf("    cmp     rax, %d\n", FALSE_VAL);
+    printf("    mov     rax, 0\n");
+    printf("    sete    al\n");
+    printf("    shl     rax, %d\n", BOOL_SHIFT);
+    printf("    or      rax, %d\n", BOOL_TAG);
+    printf("    push    rax\n");
+    printf("    ;; <-- compile_not\n");
+}
+
+void
+compile_and(Object *args) {
+    printf("    ;; --> compile_and\n");
+    char *lab_false = generate_label();
+    char *lab_exit = generate_label();
+    while (args != NULL) {
+        compile_object(args->head);
+        args = args->tail;
         printf("    pop     rax\n");
         printf("    cmp     rax, %d\n", FALSE_VAL);
-        printf("    mov     rax, 0\n");
-        printf("    sete    al\n");
-        printf("    shl     rax, %d\n", BOOL_SHIFT);
-        printf("    or      rax, %d\n", BOOL_TAG);
-        printf("    push    rax\n");
-        printf("    ;; <-- compile_logic_list\n");
-        return;
+        printf("    je      %s\n", lab_false);
     }
+    printf("    mov     rax, %d\n", TRUE_VAL);
+    printf("    push    rax\n");
+    printf("    jmp     %s\n", lab_exit);
+    printf("%s:\n", lab_false);
+    printf("    mov     rax, %d\n", FALSE_VAL);
+    printf("    push    rax\n");
+    printf("%s:\n", lab_exit);
+    free(lab_false);
+    free(lab_exit);
+    printf("    ;; <-- compile_and\n");
+}
 
-    // TODO: Make sure to stop evaluating if the condition is not met.
-    args = args->tail;
+void
+compile_or(Object *args) {
+    printf("    ;; --> compile_or\n");
+    char *lab_true = generate_label();
+    char *lab_exit = generate_label();
     while (args != NULL) {
         compile_object(args->head);
         args = args->tail;
-
-        // Current value.
-        printf("    pop     rcx\n");
-        printf("    cmp     rcx, %d\n", FALSE_VAL);
-        printf("    mov     rcx, 0\n");
-        printf("    setne   cl\n");
-
-        // Previous value.
         printf("    pop     rax\n");
         printf("    cmp     rax, %d\n", FALSE_VAL);
-        printf("    mov     rax, 0\n");
-        printf("    setne   al\n");
-
-        switch (op) {
-            case OP_AND: { printf("    and     al, cl\n"); } break;
-            case OP_OR:  { printf("    or      al, cl\n"); } break;
-            default: break;
-        }
-        printf("    shl     rax, %d\n", BOOL_SHIFT);
-        printf("    or      rax, %d\n", BOOL_TAG);
-        printf("    push    rax\n");
+        printf("    jne     %s\n", lab_true);
     }
-    printf("    ;; <-- compile_logic_list\n");
+    printf("    mov     rax, %d\n", FALSE_VAL);
+    printf("    push    rax\n");
+    printf("    jmp     %s\n", lab_exit);
+    printf("%s:\n", lab_true);
+    printf("    mov     rax, %d\n", TRUE_VAL);
+    printf("    push    rax\n");
+    printf("%s:\n", lab_exit);
+    free(lab_true);
+    free(lab_exit);
+    printf("    ;; <-- compile_or\n");
 }
 
 void
@@ -291,11 +305,11 @@ compile_proc_call(Object *obj) {
         printf("    pop     rdi\n");
         printf("    call    display\n");
     } else if (sv_equal(&obj->head->text, &STRING("not"))) {
-        compile_logic_list(OP_NOT, obj->tail);
+        compile_not(obj->tail);
     } else if (sv_equal(&obj->head->text, &STRING("and"))) {
-        compile_logic_list(OP_AND, obj->tail);
+        compile_and(obj->tail);
     } else if (sv_equal(&obj->head->text, &STRING("or"))) {
-        compile_logic_list(OP_OR, obj->tail);
+        compile_or(obj->tail);
     } else if (sv_equal(&obj->head->text, &STRING("="))) {
         compile_cmp_list(OP_EQUAL, obj->tail);
     } else if (sv_equal(&obj->head->text, &STRING(">"))) {
-- 
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