4.59

    4.47 is the better one

    loop part in 4.47

    1. L4:
    2.   mrmovq 8(%rax), %r9
    3.   mrmovq (%rax), %r10
    4.   rrmovq %r9, %r8
    5.   subq %r10, %r8
    6.   jge L3
    7.   rmmovq %r10, 8(%rax)
    8.   rmmovq %r9, (%rax)

    50% jge is right, run 5 instructions; 50% jge is wrong, run 7 instructions and 2
    nop bubble. so Cycles Per Loop is 50% 5 + (7 + 2) 50% = 7

    loop part in 4.48

    1. L4:
    2.   mrmovq 8(%rax), %r9
    3.   mrmovq (%rax), %r10
    4.   rrmovq %r9, %r8
    5.   subq %r10, %r8
    6.   cmovl %r9, %r11
    7.   cmovl %r10, %r9
    8.   cmovl %r11, %r10
    9.   rmmovq %r9, 8(%rax)
    10.   rmmovq %r10, (%rax)

    Cycles Per Loop is 9

    loop part in 4.49

    1. L4:
    2.   mrmovq 8(%rax), %r9
    3.   mrmovq (%rax), %r10
    4.   rrmovq %r9, %r8
    5.   rrmovq %r10, %r11
    6.   xorq %r9, %r10
    7.   subq %r11, %r8
    8.   cmovge %r11, %r9
    9.   xorq %r10, %r9
    10.   xorq %r9, %r10
    11.   rmmovq %r9, 8(%rax)
    12.   rmmovq %r10, (%rax)

    Cycles Per Loop is 11