From 3aab67401eed61ca8a43a8867103fe8964081c0d Mon Sep 17 00:00:00 2001
From: cuz <cuz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Sat, 28 Sep 2002 19:41:00 +0000
Subject: [PATCH] Fixed the result of the % operator for ints

git-svn-id: svn://svn.cc65.org/cc65/trunk@1408 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 libsrc/runtime/div.s   | 25 ++++++++++++++++++++-----
 libsrc/runtime/mod.s   | 25 ++++++++++++++++++++-----
 libsrc/runtime/shelp.s | 26 ++++----------------------
 3 files changed, 44 insertions(+), 32 deletions(-)

diff --git a/libsrc/runtime/div.s b/libsrc/runtime/div.s
index b995b9e87..e419dedff 100644
--- a/libsrc/runtime/div.s
+++ b/libsrc/runtime/div.s
@@ -8,15 +8,30 @@
 ; values if $8000, in which case the negate will fail.
 
        	.export		tosdiva0, tosdivax
-	.import		popsargs, udiv16, adjsres
-	.importzp	sreg
+	.import		popsargs, udiv16, negax
+	.importzp	sreg, tmp1, tmp2
 
 tosdiva0:
       	ldx	#0
 tosdivax:
 	jsr	popsargs	; Get arguments from stack, adjust sign
       	jsr	udiv16		; Do the division
-   	lda	sreg		; Result is in sreg, remainder in ptr1
-   	ldx	sreg+1
-	jmp	adjsres	      	; Adjust the sign of the result if needed
+        ldx     sreg+1          ; Load high byte of result
+
+; Adjust the sign of the result. tmp1 contains the high byte of the left
+; operand, tmp2 contains the high byte of the right operand.
+
+        lda     tmp1
+        eor     tmp2
+        bpl     Pos             ; Jump if sign of result positive
+
+; Result is negative
+
+        lda     sreg            ; Load low byte of result
+        jmp     negax           ; Adjust the sign
+
+; Result is positive
+
+Pos:    lda     sreg
+        rts
 
diff --git a/libsrc/runtime/mod.s b/libsrc/runtime/mod.s
index 9e2a73ed8..1a97c6592 100644
--- a/libsrc/runtime/mod.s
+++ b/libsrc/runtime/mod.s
@@ -8,16 +8,31 @@
 ; values if $8000, in which case the negate will fail.
 
        	.export		tosmoda0, tosmodax
-	.import		popsargs, udiv16, adjsres
-	.importzp	ptr1
+	.import		popsargs, udiv16, negax
+	.importzp	ptr1, tmp1
 
 tosmoda0:
       	ldx	#0
 tosmodax:
 	jsr	popsargs	; Get arguments from stack, adjust sign
       	jsr	udiv16		; Do the division
-      	lda	ptr1		; Result is in sreg, remainder in ptr1
-      	ldx	ptr1+1
-	jmp	adjsres		; Adjust the sign of the result if needed
+      	ldx	ptr1+1          ; Load high byte of result
 
+; Adjust the sign of the result. tmp1 contains the high byte of the left
+; operand, tmp2 contains the high byte of the right operand. The sign of
+; the result of the modulo operation is the same as that of the left
+; operand
+
+        lda     tmp1
+        bpl     Pos             ; Jump if sign of result positive
+
+; Result is negative
+
+        lda     ptr1            ; Load low byte of result
+        jmp     negax           ; Adjust the sign
+
+; Result is positive
+
+Pos:    lda     ptr1
+        rts
 
diff --git a/libsrc/runtime/shelp.s b/libsrc/runtime/shelp.s
index 631ff4783..d4f55b1e2 100644
--- a/libsrc/runtime/shelp.s
+++ b/libsrc/runtime/shelp.s
@@ -7,12 +7,12 @@
 ; When negating values, we will ignore the possibility here, that one of the
 ; values if $8000, in which case the negate will fail.
 
-       	.export		popsargs, adjsres
+       	.export		popsargs
 	.import		negax, popax
 	.importzp	sreg, tmp1, tmp2, ptr4
 
 popsargs:
-      	stx	tmp1	       	; Remember sign
+       	stx    	tmp2	       	; Remember sign
       	cpx	#0
       	bpl	L1
       	jsr	negax	       	; Negate accumulator
@@ -20,29 +20,11 @@ L1:   	sta	ptr4
       	stx	ptr4+1 	       	; Save right operand
 
       	jsr	popax
-      	stx	tmp2	       	; Remember sign
+      	stx	tmp1	       	; Remember sign
       	cpx	#0
       	bpl	L2
       	jsr	negax
 L2:   	sta	sreg
       	stx	sreg+1
-
-; Calculate the sign of the result, that is sign(op1) * sign(op2)
-
-      	lda	tmp1
-      	eor	tmp2
-      	sta	tmp2  	       	; Save it across call
-L3:	rts
-
-; Adjust the result of a mod/div/mul operation
-
-adjsres:
-
-; Check if we must adjust the sign
-
-      	ldy	tmp2
-      	bpl	L3
-      	jmp    	negax 	       	; Adjust sign
-
-
+        rts
 
-- 
2.39.5