/* checksum.S: Sparc V9 optimized checksum code.
*
* Copyright(C) 1995 Linus Torvalds
* Copyright(C) 1995 Miguel de Icaza
* Copyright(C) 1996, 2000 David S. Miller
* Copyright(C) 1997 Jakub Jelinek
*
* derived from:
* Linux/Alpha checksum c-code
* Linux/ix86 inline checksum assembly
* RFC1071 Computing the Internet Checksum (esp. Jacobsons m68k code)
* David Mosberger-Tang for optimized reference c-code
* BSD4.4 portable checksum routine
*/
.text
csum_partial_fix_alignment:
/* We checked for zero length already, so there must be
* at least one byte.
*/
be,pt %icc, 1f
nop
ldub [%o0 + 0x00], %o4
add %o0, 1, %o0
sub %o1, 1, %o1
1: andcc %o0, 0x2, %g0
be,pn %icc, csum_partial_post_align
cmp %o1, 2
blu,pn %icc, csum_partial_end_cruft
nop
lduh [%o0 + 0x00], %o5
add %o0, 2, %o0
sub %o1, 2, %o1
ba,pt %xcc, csum_partial_post_align
add %o5, %o4, %o4
.align 32
.globl csum_partial
csum_partial: /* %o0=buff, %o1=len, %o2=sum */
prefetch [%o0 + 0x000], #n_reads
clr %o4
prefetch [%o0 + 0x040], #n_reads
brz,pn %o1, csum_partial_finish
andcc %o0, 0x3, %g0
/* We "remember" whether the lowest bit in the address
* was set in %g7. Because if it is, we have to swap
* upper and lower 8 bit fields of the sum we calculate.
*/
bne,pn %icc, csum_partial_fix_alignment
andcc %o0, 0x1, %g7
csum_partial_post_align:
prefetch [%o0 + 0x080], #n_reads
andncc %o1, 0x3f, %o3
prefetch [%o0 + 0x0c0], #n_reads
sub %o1, %o3, %o1
brz,pn %o3, 2f
prefetch [%o0 + 0x100], #n_reads
/* So that we don't need to use the non-pairing
* add-with-carry instructions we accumulate 32-bit
* values into a 64-bit register. At the end of the
* loop we fold it down to 32-bits and so on.
*/
prefetch [%o0 + 0x140], #n_reads
1: lduw [%o0 + 0x00], %o5
lduw [%o0 + 0x04], %g1
lduw [%o0 + 0x08], %g2
add %o4, %o5, %o4
lduw [%o0 + 0x0c], %g3
add %o4, %g1, %o4
lduw [%o0 + 0x10], %o5
add %o4, %g2, %o4
lduw [%o0 + 0x14], %g1
add %o4, %g3, %o4
lduw [%o0 + 0x18], %g2
add %o4, %o5, %o4
lduw [%o0 + 0x1c], %g3
add %o4, %g1, %o4
lduw [%o0 + 0x20], %o5
add %o4, %g2, %o4
lduw [%o0 + 0x24], %g1
add %o4, %g3, %o4
lduw [%o0 + 0x28], %g2
add %o4, %o5, %o4
lduw [%o0 + 0x2c], %g3
add %o4, %g1, %o4
lduw [%o0 + 0x30], %o5
add %o4, %g2, %o4
lduw [%o0 + 0x34], %g1
add %o4, %g3, %o4
lduw [%o0 + 0x38], %g2
add %o4, %o5, %o4
lduw [%o0 + 0x3c], %g3
add %o4, %g1, %o4
prefetch [%o0 + 0x180], #n_reads
add %o4, %g2, %o4
subcc %o3, 0x40, %o3
add %o0, 0x40, %o0
bne,pt %icc, 1b
add %o4, %g3, %o4
2: and %o1, 0x3c, %o3
brz,pn %o3, 2f
sub %o1, %o3, %o1
1: lduw [%o0 + 0x00], %o5
subcc %o3, 0x4, %o3
add %o0, 0x4, %o0
bne,pt %icc, 1b
add %o4, %o5, %o4
2:
/* fold 64-->32 */
srlx %o4, 32, %o5
srl %o4, 0, %o4
add %o4, %o5, %o4
srlx %o4, 32, %o5
srl %o4, 0, %o4
add %o4, %o5, %o4
/* fold 32-->16 */
sethi %hi(0xffff0000), %g1
srl %o4, 16, %o5
andn %o4, %g1, %g2
add %o5, %g2, %o4
srl %o4, 16, %o5
andn %o4, %g1, %g2
add %o5, %g2, %o4
csum_partial_end_cruft:
/* %o4 has the 16-bit sum we have calculated so-far. */
cmp %o1, 2
blu,pt %icc, 1f
nop
lduh [%o0 + 0x00], %o5
sub %o1, 2, %o1
add %o0, 2, %o0
add %o4, %o5, %o4
1: brz,pt %o1, 1f
nop
ldub [%o0 + 0x00], %o5
sub %o1, 1, %o1
add %o0, 1, %o0
sllx %o5, 8, %o5
add %o4, %o5, %o4
1:
/* fold 32-->16 */
sethi %hi(0xffff0000), %g1
srl %o4, 16, %o5
andn %o4, %g1, %g2
add %o5, %g2, %o4
srl %o4, 16, %o5
andn %o4, %g1, %g2
add %o5, %g2, %o4
1: brz,pt %g7, 1f
nop
/* We started with an odd byte, byte-swap the result. */
srl %o4, 8, %o5
and %o4, 0xff, %g1
sll %g1, 8, %g1
or %o5, %g1, %o4
1: add %o2, %o4, %o2
csum_partial_finish:
retl
mov %o2, %o0
