2 ; Ullrich von Bassewitz, 2010-11-02
4 ; CC65 runtime: 8x8 => 16 multiplication
7 .export umul8x8r16, umul8x8r16m
11 ;---------------------------------------------------------------------------
12 ; 8x8 => 16 multiplication routine.
14 ; lhs rhs result result also in
15 ; -------------------------------------------------------------
16 ; ptr1-lo ptr3-lo ax ptr1
23 ldy #8 ; Number of bits
24 lsr ptr1 ; Get first bit of lhs into carry
33 stx ptr1+1 ; Result in a/x and ptr1
34 lda ptr1 ; Load the result