From: Eric Dumazet
> Sent: 05 January 2016 22:19
> To: Tom Herbert
> You might add a comment telling the '4' comes from length of 'adcq
> 6*8(%rdi),%rax' instruction, and that the 'nop' is to compensate that
> 'adcq 0*8(%rdi),%rax' is using 3 bytes instead.
>
> We also could use .byte 0x48, 0x13, 0x47, 0x00 to force a 4 bytes
> instruction and remove the nop.
>
>
> + lea 20f(, %rcx, 4), %r11
> + clc
> + jmp *%r11
> +
> +.align 8
> + adcq 6*8(%rdi),%rax
> + adcq 5*8(%rdi),%rax
> + adcq 4*8(%rdi),%rax
> + adcq 3*8(%rdi),%rax
> + adcq 2*8(%rdi),%rax
> + adcq 1*8(%rdi),%rax
> + adcq 0*8(%rdi),%rax // could force a 4 byte instruction (.byte
> 0x48, 0x13, 0x47, 0x00)
> + nop
> +20: /* #quads % 8 jump table base */
Or move label at the top (after the .align) and adjust the maths.
You could add a second label after the first adcq and use the
difference between them for the '4'.
David
