x86_64 no loop needed: movabsq $3472328296227680304, %rdx movzbl %dil, %eax movabsq $-9205322385119247871, %rdi imulq %rdi, %rax movabsq $7

x86_64 no loop needed: movabsq $3472328296227680304, %rdx movzbl %dil, %eax movabsq $-9205322385119247871, %rdi imulq %rdi, %rax movabsq $72340172838076673, %rdi shrq $7, %rax andq %rdi, %rax addq %rdx, %rax movq %rax, (%rsi) 6502 with a loop: LDX #$08 loop LSR $EB LDA #$30 ADC #$00 DEX STA result,X BNE loop