Fix behaviour of numerical comparisons

1 files changed, 19 insertions, 29 deletions

diff --git a/src/compiler.h b/src/compiler.h
index e511b7c..ff2c6e0 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -189,13 +189,8 @@ void
 compile_cmp_list(OpType op, Object* args) {
     printf("    ;; --> compile_cmp_list\n");
     compile_object(args->head);
-
-    // TODO: Make sure to stop evaluating if the condition is not met.
-    // FIXME: Only working for two argument lists right now because we can't
-    // accumulate the bool and compare it with an int. We can fix it by passing
-    // two values on the stack (previous value and current result) or by only
-    // passing a previous value and having a conditional jump (need labels for
-    // that).
+    char *lab_false = generate_label();
+    char *lab_exit = generate_label();
     args = args->tail;
     while (args != NULL) {
         compile_object(args->head);
@@ -203,37 +198,32 @@ compile_cmp_list(OpType op, Object* args) {
 
         // Current value.
         printf("    pop     rcx\n");
-        printf("    sar     rcx, %d\n", FIXNUM_SHIFT);
 
         // Previous value.
         printf("    pop     rax\n");
-        printf("    sar     rax, %d\n", FIXNUM_SHIFT);
 
+        // Comparison.
         printf("    cmp     rax, rcx\n");
-        printf("    mov     rax, 0\n");
-
         switch (op) {
-            case OP_EQUAL: {
-                printf("    sete    al\n");
-            } break;
-            case OP_GREATER: {
-                printf("    setg    al\n");
-            } break;
-            case OP_LESS: {
-                printf("    setl    al\n");
-            } break;
-            case OP_GREATER_EQ: {
-                printf("    setge   al\n");
-            } break;
-            case OP_LESS_EQ: {
-                printf("    setle   al\n");
-            } break;
+            case OP_EQUAL:      { printf("    jne     %s\n", lab_false); } break;
+            case OP_GREATER:    { printf("    jle     %s\n", lab_false); } break;
+            case OP_LESS:       { printf("    jge     %s\n", lab_false); } break;
+            case OP_GREATER_EQ: { printf("    jl      %s\n", lab_false); } break;
+            case OP_LESS_EQ:    { printf("    jg      %s\n", lab_false); } break;
             default: break;
         }
-        printf("    shl     rax, %d\n", BOOL_SHIFT);
-        printf("    or      rax, %d\n", BOOL_TAG);
-        printf("    push    rax\n");
+        printf("    push    rcx\n");
     }
+    printf("    pop     rcx\n");
+    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_cmp_list\n");
 }