optimized calloc zero-filling

Author: ZERICO2005

src/libc/allocator.src

@@ -7,24 +7,33 @@
 _calloc:
 	pop	de
 	pop	bc
-	ex	(sp),hl
+	ex	(sp), hl
 	push	bc
 	push	de
 	call	__imulu
 	push	hl
 	push	hl
 	call	_malloc
-	pop	de
-	add	hl,de
-	xor	a,a
-	sbc	hl,de
-	ld	e,a
-	push	de
+	pop	bc	; reset SP
+	; test for NULL
+	add	hl, bc
+	or	a, a
+	sbc	hl, bc
+	pop	bc	; BC = size
+	ret	z	; return NULL
+	; inlined bzero
 	push	hl
-	call	nz,_memset
-	pop	de
-	pop	de
-	pop	de
+	ex	de, hl	; DE = dest
+	; test if the size is zero
+	scf
+	sbc	hl, hl
+	add	hl, bc
+	jr	nc, .finish
+	; large region of all zeros on the Ti84CE
+	ld	hl, $E40000	; HL = src
+	ldir
+.finish:
+	pop	hl	; return value
 	ret
 
 if defined ALLOCATOR_SIMPLE

test/standalone/asprintf_fprintf/src/main.c

@@ -415,6 +415,12 @@ int memccpy_tests(void) {
         return __LINE__;
     }
 
+    /* check that no crashes occur with small calloc sizes */
+    buf = (char*)calloc(1, sizeof(char));
+    free(buf);
+    buf = (char*)calloc(0, sizeof(char));
+    free(buf);
+
     buf = (char*)calloc(file_size + 1, sizeof(char));
     if (buf == NULL) {
         perror("calloc failure");