Merge pull request #99 from groessler/something_to_pull

[cc65] / libsrc / runtime / mulax7.s

diff --git a/libsrc/runtime/mulax7.s b/libsrc/runtime/mulax7.s
index b7ce28cffacf678658d70719f0ae619c149c41f8..90313180c198edb927b32713c84238dc9634e075 100644 (file)
--- a/libsrc/runtime/mulax7.s
+++ b/libsrc/runtime/mulax7.s
@@ -1,31 +1,32 @@
 ;
-; Ullrich von Bassewitz, 16.03.2002
+; Piotr Fusik, 24.10.2003
+; originally by Ullrich von Bassewitz
 ;
-; CC65 runtime: Multiply the primary register
+; CC65 runtime: Multiply the primary register by 7
 ;
 
-       .export         mulax7
-       .importzp       ptr1, tmp1
+        .export         mulax7
+        .importzp       ptr1
 
-.proc  mulax7
+.proc   mulax7
 
-       sta     ptr1
-       stx     ptr1+1
-       stx     tmp1
-       asl     a
-       rol     tmp1                    ; * 2
-       asl     a
-       rol     tmp1                    ; * 4
-       asl     a
-       rol     tmp1                    ; * 8
-       sec
-       sbc     ptr1
-       pha
-       lda     tmp1
-       sbc     ptr1+1                  ; * (8 - 1)
-       tax
-       pla
-       rts
+        sta     ptr1
+        stx     ptr1+1
+        asl     a
+        rol     ptr1+1                  ; * 2
+        asl     a
+        rol     ptr1+1                  ; * 4
+        asl     a
+        rol     ptr1+1                  ; * 8
+        sec
+        sbc     ptr1
+        pha
+        txa
+        eor     #$ff
+        adc     ptr1+1                  ; * (8 - 1)
+        tax
+        pla
+        rts
 
 .endproc