kickc/src/main/fragment/mos6502-common/vwsm1=vwsm1_plus_pbsz2_derefidx_vbuyy.asm

clc
lda ({z2}),y
adc {m1}
sta {m1}
lda ({z2}),y
ora #$7f
bmi !+
lda #0
!:
adc {m1}+1
sta {m1}+1