bcopy/memmove optimization broken ?

[Alexandre Martins]

Hi all

I see in the kernel code of bcopy/memmove an optimization if the copied region 
don't overlap:

https://svnweb.freebsd.org/base/head/sys/arm/arm/support.S?view=annotate#l403

I'm a newbie in ARM assembly, so, sorry if i'm wrong, but
 - R0 is the dst (1st parameter)
 - R1 is the src (2nd parameter)

So :
 subcc r3, r0, r1 /* if (dst > src) r3 = dst - src */
 subcs r3, r1, r0 /* if (src > dsr) r3 = src - dst */
 cmp r3, r2 /* if (r3 < len) we have an overlap */
 bcc PIC_SYM(_C_LABEL(memcpy), PLT)

Seems to be inverted. Should it be that ? :
 subcs r3, r0, r1 /* if (dst > src) r3 = dst - src */
 subcc r3, r1, r0 /* if (src > dsr) r3 = src - dst */
 cmp r3, r2 /* if (r3 < len) we have an overlap */
 bcs PIC_SYM(_C_LABEL(memcpy), PLT)


Best regards

-- 
Alexandre Martins
STORMSHIELD

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