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- Fix REDUCE16 to ignore the upper 32-bits of the input operand.

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- Shift a leading misaligned quad to compensate for the implicit shift
  in the "ldlo.q" instruction. (And remove the "XXX:" comment which correctly
  hinted that this might be necessary).
- Clean up some comments.
This commit is contained in:
scw 2002-10-22 12:22:43 +00:00
parent 7a7914f91a
commit 8496cdaeb7
1 changed files with 16 additions and 20 deletions
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36
sys/arch/sh5/sh5/in_cksum.S
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@ -1,4 +1,4 @@
/* $NetBSD: in_cksum.S,v 1.2 2002/10/19 13:17:33 scw Exp $ */
/* $NetBSD: in_cksum.S,v 1.3 2002/10/22 12:22:43 scw Exp $ */
/*
* Copyright 2002 Wasabi Systems, Inc.
@ -82,12 +82,15 @@
#define REDUCE16(i, result) \
mshflo.w i, r63, r0 ;\
shlri i, 16, i ;\
add r0, i, i ;\
addz.l r0, i, i ;\
mshflo.w i, r63, r0 ;\
shlri i, 16, i ;\
add r0, i, result
/*
* The main in*_cksum() workhorse...
*
* Entry parameters:
*
* r3 Buffer length
@ -97,14 +100,14 @@
*
* Returns:
*
* r7 Accumulated sum as two pairs of "carry:sum" words.
* r7 Accumulated 64-bit sum
*
* Trashes:
* r0, r1, r3, r4, r19, r20, r21, r22
* tr0, tr1, tr2
*/
Lcksumdata:
ASENTRY(cksumdata)
movi 0, r7
ld.b r4, 0, r63 /* Pre-fetch the start of the buffer */
ptabs/u r18, tr0
@ -112,21 +115,19 @@ Lcksumdata:
/*
* We first have to quad-align the buffer.
*
* XXX: We may have to shift the result of the following "ldlo.q"
* depending on the buffer alignment, particularly for odd addresses,
* in the same way as we do for the "ldhi.q" in Lend_game.
*/
pta/u Lalready_aligned, tr2
xori r4, 0x7, r0
andi r0, 0x7, r0
andi r4, 0x7, r1
xori r1, 0x7, r0
beqi/u r0, 0x7, tr2 /* Jump if already quad aligned */
addi r0, 1, r0 /* r0 == # bytes to next quad */
bgtu/u r0, r3, tr1 /* Not enough bytes left to make it */
ldlo.q r4, 0, r19 /* Fetch 1 to 4 words */
ldlo.q r4, 0, r19 /* Fetch 1 to 7 bytes */
shlli r1, 3, r1
add r4, r0, r4 /* r4 is now quad-aligned */
sub r3, r0, r3 /* Update remaining length */
ADDC (r19, r7, r7) /* Accumulate the words we just read */
shlld r19, r1, r19
ADDC (r19, r7, r7) /* Accumulate the bytes we just read */
beq/u r3, r63, tr0 /* Return to caller if done */
/*
@ -152,15 +153,10 @@ Lalready_aligned:
/*
* At this point:
*
* r0 == 0x00 Enter loop at 1st load.
* r0 == 0x08 Enter loop at 2nd load.
* r0 == 0x10 Enter loop at 3rd load.
* r0 == 0x18 Enter loop at 4th load.
*
* r3 == # of bytes remaining, AFTER loop entry.
* r4 -> *next* 32-byte aligned chunk of buffer.
*
* The "big_loop" checksums 16 words at a time.
* The "big_loop" checksums 32 bytes at a time.
*/
Lbig_loop:
@ -223,7 +219,6 @@ Lend_game:
ADDC (r22, r7, r7)
blink tr0, r63
/*
* int in_cksum(struct mbuf *m, int len)
*/
@ -243,7 +238,7 @@ ENTRY(in_cksum)
* r6 == len
*/
Lcksum_top:
pta/u Lcksumdata, tr4
pta/u _ASM_LABEL(cksumdata), tr4
pta/u Lcksum_loop, tr3
movi 0, r7
movi 0, r8
@ -363,3 +358,4 @@ Lout_of_mbufs:
Lmbuf_msg:
.asciz "cksum: out of mbufs\n"
#endif /* INET || INET6 */