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Both csum_partial() and the csum_partial_copy*() family of routines forget to do a final fold on the computed checksum value on sparc64. So do the standard Sparc "add + set condition codes, add carry" sequence, then make sure the high 32-bits of the return value are clear. Based upon some excellent detective work and debugging done by Richard Braun and Samuel Thibault. Signed-off-by: David S. Miller <davem@davemloft.net>
174 lines
3.8 KiB
ArmAsm
174 lines
3.8 KiB
ArmAsm
/* checksum.S: Sparc V9 optimized checksum code.
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*
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* Copyright(C) 1995 Linus Torvalds
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* Copyright(C) 1995 Miguel de Icaza
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* Copyright(C) 1996, 2000 David S. Miller
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* Copyright(C) 1997 Jakub Jelinek
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*
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* derived from:
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* Linux/Alpha checksum c-code
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* Linux/ix86 inline checksum assembly
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* RFC1071 Computing the Internet Checksum (esp. Jacobsons m68k code)
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* David Mosberger-Tang for optimized reference c-code
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* BSD4.4 portable checksum routine
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*/
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.text
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csum_partial_fix_alignment:
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/* We checked for zero length already, so there must be
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* at least one byte.
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*/
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be,pt %icc, 1f
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nop
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ldub [%o0 + 0x00], %o4
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add %o0, 1, %o0
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sub %o1, 1, %o1
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1: andcc %o0, 0x2, %g0
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be,pn %icc, csum_partial_post_align
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cmp %o1, 2
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blu,pn %icc, csum_partial_end_cruft
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nop
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lduh [%o0 + 0x00], %o5
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add %o0, 2, %o0
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sub %o1, 2, %o1
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ba,pt %xcc, csum_partial_post_align
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add %o5, %o4, %o4
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.align 32
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.globl csum_partial
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csum_partial: /* %o0=buff, %o1=len, %o2=sum */
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prefetch [%o0 + 0x000], #n_reads
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clr %o4
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prefetch [%o0 + 0x040], #n_reads
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brz,pn %o1, csum_partial_finish
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andcc %o0, 0x3, %g0
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/* We "remember" whether the lowest bit in the address
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* was set in %g7. Because if it is, we have to swap
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* upper and lower 8 bit fields of the sum we calculate.
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*/
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bne,pn %icc, csum_partial_fix_alignment
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andcc %o0, 0x1, %g7
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csum_partial_post_align:
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prefetch [%o0 + 0x080], #n_reads
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andncc %o1, 0x3f, %o3
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prefetch [%o0 + 0x0c0], #n_reads
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sub %o1, %o3, %o1
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brz,pn %o3, 2f
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prefetch [%o0 + 0x100], #n_reads
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/* So that we don't need to use the non-pairing
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* add-with-carry instructions we accumulate 32-bit
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* values into a 64-bit register. At the end of the
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* loop we fold it down to 32-bits and so on.
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*/
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prefetch [%o0 + 0x140], #n_reads
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1: lduw [%o0 + 0x00], %o5
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lduw [%o0 + 0x04], %g1
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lduw [%o0 + 0x08], %g2
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add %o4, %o5, %o4
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lduw [%o0 + 0x0c], %g3
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add %o4, %g1, %o4
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lduw [%o0 + 0x10], %o5
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add %o4, %g2, %o4
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lduw [%o0 + 0x14], %g1
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add %o4, %g3, %o4
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lduw [%o0 + 0x18], %g2
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add %o4, %o5, %o4
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lduw [%o0 + 0x1c], %g3
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add %o4, %g1, %o4
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lduw [%o0 + 0x20], %o5
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add %o4, %g2, %o4
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lduw [%o0 + 0x24], %g1
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add %o4, %g3, %o4
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lduw [%o0 + 0x28], %g2
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add %o4, %o5, %o4
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lduw [%o0 + 0x2c], %g3
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add %o4, %g1, %o4
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lduw [%o0 + 0x30], %o5
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add %o4, %g2, %o4
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lduw [%o0 + 0x34], %g1
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add %o4, %g3, %o4
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lduw [%o0 + 0x38], %g2
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add %o4, %o5, %o4
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lduw [%o0 + 0x3c], %g3
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add %o4, %g1, %o4
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prefetch [%o0 + 0x180], #n_reads
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add %o4, %g2, %o4
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subcc %o3, 0x40, %o3
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add %o0, 0x40, %o0
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bne,pt %icc, 1b
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add %o4, %g3, %o4
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2: and %o1, 0x3c, %o3
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brz,pn %o3, 2f
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sub %o1, %o3, %o1
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1: lduw [%o0 + 0x00], %o5
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subcc %o3, 0x4, %o3
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add %o0, 0x4, %o0
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bne,pt %icc, 1b
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add %o4, %o5, %o4
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2:
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/* fold 64-->32 */
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srlx %o4, 32, %o5
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srl %o4, 0, %o4
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add %o4, %o5, %o4
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srlx %o4, 32, %o5
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srl %o4, 0, %o4
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add %o4, %o5, %o4
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/* fold 32-->16 */
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sethi %hi(0xffff0000), %g1
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srl %o4, 16, %o5
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andn %o4, %g1, %g2
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add %o5, %g2, %o4
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srl %o4, 16, %o5
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andn %o4, %g1, %g2
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add %o5, %g2, %o4
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csum_partial_end_cruft:
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/* %o4 has the 16-bit sum we have calculated so-far. */
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cmp %o1, 2
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blu,pt %icc, 1f
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nop
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lduh [%o0 + 0x00], %o5
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sub %o1, 2, %o1
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add %o0, 2, %o0
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add %o4, %o5, %o4
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1: brz,pt %o1, 1f
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nop
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ldub [%o0 + 0x00], %o5
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sub %o1, 1, %o1
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add %o0, 1, %o0
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sllx %o5, 8, %o5
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add %o4, %o5, %o4
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1:
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/* fold 32-->16 */
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sethi %hi(0xffff0000), %g1
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srl %o4, 16, %o5
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andn %o4, %g1, %g2
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add %o5, %g2, %o4
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srl %o4, 16, %o5
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andn %o4, %g1, %g2
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add %o5, %g2, %o4
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1: brz,pt %g7, 1f
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nop
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/* We started with an odd byte, byte-swap the result. */
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srl %o4, 8, %o5
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and %o4, 0xff, %g1
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sll %g1, 8, %g1
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or %o5, %g1, %o4
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1: addcc %o2, %o4, %o2
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addc %g0, %o2, %o2
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csum_partial_finish:
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retl
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srl %o2, 0, %o0
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