Fix for 8x16 multiplication if operants are swapped.

2018-05-22 18:35:05 +02:00
parent ba2c6d9008
commit 808d3ab471
1 changed files with 2 additions and 1 deletions
--- a/libsrc/runtime/mul.s
+++ b/libsrc/runtime/mul.s
@@ -62,7 +62,8 @@ tosumulax:
@L4:    ldy     ptr1            ; Save right operand (8 bit)
        ldx     ptr4            ; Copy left 16 bit operand to right
        stx     ptr1
-        ldx     ptr4+1          ; Don't store, this is done later
+        ldx     ptr4+1          ; swap high-byte too
+        stx     ptr1+1
        sty     ptr4            ; Copy low 8 bit of right op to left
        ldy     #8
        jmp     mul8x16a