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Subject[PATCH 2/2] lib: Fix 32-bit sparc udiv_qrnnd() definition in mpilib's longlong.h
From

This copy of longlong.h is extremely dated and results in compile
errors on sparc32 when MPILIB is enabled, copy over the more uptodate
implementation from arch/sparc/math/sfp-util_32.h

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
lib/mpi/longlong.h | 44 +++++++++++++++++++++++++++++++++-----------
1 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h
index b87487b..29f9862 100644
--- a/lib/mpi/longlong.h
+++ b/lib/mpi/longlong.h
@@ -1200,18 +1200,40 @@ do { \
"r" ((USItype)(v)) \
: "%g1", "%g2" __AND_CLOBBER_CC)
#define UMUL_TIME 39 /* 39 instructions */
-#endif
-#ifndef udiv_qrnnd
-#ifndef LONGLONG_STANDALONE
+/* It's quite necessary to add this much assembler for the sparc.
+ The default udiv_qrnnd (in C) is more than 10 times slower! */
#define udiv_qrnnd(q, r, n1, n0, d) \
-do { USItype __r; \
- (q) = __udiv_qrnnd(&__r, (n1), (n0), (d)); \
- (r) = __r; \
-} while (0)
- extern USItype __udiv_qrnnd();
-#define UDIV_TIME 140
-#endif /* LONGLONG_STANDALONE */
-#endif /* udiv_qrnnd */
+ __asm__ ("! Inlined udiv_qrnnd\n\t" \
+ "mov 32,%%g1\n\t" \
+ "subcc %1,%2,%%g0\n\t" \
+ "1: bcs 5f\n\t" \
+ "addxcc %0,%0,%0 ! shift n1n0 and a q-bit in lsb\n\t" \
+ "sub %1,%2,%1 ! this kills msb of n\n\t" \
+ "addx %1,%1,%1 ! so this can't give carry\n\t" \
+ "subcc %%g1,1,%%g1\n\t" \
+ "2: bne 1b\n\t" \
+ "subcc %1,%2,%%g0\n\t" \
+ "bcs 3f\n\t" \
+ "addxcc %0,%0,%0 ! shift n1n0 and a q-bit in lsb\n\t" \
+ "b 3f\n\t" \
+ "sub %1,%2,%1 ! this kills msb of n\n\t" \
+ "4: sub %1,%2,%1\n\t" \
+ "5: addxcc %1,%1,%1\n\t" \
+ "bcc 2b\n\t" \
+ "subcc %%g1,1,%%g1\n\t" \
+ "! Got carry from n. Subtract next step to cancel this carry.\n\t" \
+ "bne 4b\n\t" \
+ "addcc %0,%0,%0 ! shift n1n0 and a 0-bit in lsb\n\t" \
+ "sub %1,%2,%1\n\t" \
+ "3: xnor %0,0,%0\n\t" \
+ "! End of inline udiv_qrnnd\n" \
+ : "=&r" ((USItype)(q)), \
+ "=&r" ((USItype)(r)) \
+ : "r" ((USItype)(d)), \
+ "1" ((USItype)(n1)), \
+ "0" ((USItype)(n0)) : "%g1", "cc")
+#define UDIV_TIME (3+7*32) /* 7 instructions/iteration. 32 iterations. */
+#endif
#endif /* __sparc__ */

/***************************************
--
1.7.6.401.g6a319


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