Fixed a bug

[cc65] / libsrc / runtime / lsub.s

diff --git a/libsrc/runtime/lsub.s b/libsrc/runtime/lsub.s
index 8854e9e504d12305a1fb04d3a54e8e24232317bf..0ba716a9d91f33ee6b7bfe97cafd8fc2a6d1dfd2 100644 (file)
--- a/libsrc/runtime/lsub.s
+++ b/libsrc/runtime/lsub.s
@@ -9,19 +9,18 @@
 ;
        .export         tossubeax
        .import         addysp1
-       .importzp       sp, sreg, tmp1, tmp2
+       .importzp       sp, sreg
 
 tossubeax:
        ldy     #0
                sec
-       sta     tmp1
-       lda     (sp),y
-       sbc     tmp1            ; byte 0
-       sta     tmp2            ; use as temp storage
+       eor     #$FF
+               adc     (sp),y          ; byte 0
+               pha                     ; Save low byte
        iny
-       stx     tmp1
-       lda     (sp),y
-       sbc     tmp1            ; byte 1
+       txa
+       eor     #$FF
+       adc     (sp),y          ; byte 1
        tax
        iny
        lda     (sp),y
@@ -31,6 +30,6 @@ tossubeax:
        lda     (sp),y
        sbc     sreg+1          ; byte 3
        sta     sreg+1
-       lda     tmp2            ; load byte 0
-               jmp     addysp1         ; drop TOS
+       pla                     ; Restore byte 0
+               jmp     addysp1         ; Drop TOS