Add libgmp 6.2.0 to third_party
Don't build it yet. That will come in the next review.
Change-Id: Idf3266558165e5ab45f4a41c98cc8c838c8244d5
diff --git a/third_party/gmp/mpn/powerpc32/diveby3.asm b/third_party/gmp/mpn/powerpc32/diveby3.asm
new file mode 100644
index 0000000..288a7d3
--- /dev/null
+++ b/third_party/gmp/mpn/powerpc32/diveby3.asm
@@ -0,0 +1,93 @@
+dnl PowerPC-32 mpn_divexact_by3 -- mpn by 3 exact division
+
+dnl Copyright 2002, 2003, 2005, 2006 Free Software Foundation, Inc.
+
+dnl This file is part of the GNU MP Library.
+dnl
+dnl The GNU MP Library is free software; you can redistribute it and/or modify
+dnl it under the terms of either:
+dnl
+dnl * the GNU Lesser General Public License as published by the Free
+dnl Software Foundation; either version 3 of the License, or (at your
+dnl option) any later version.
+dnl
+dnl or
+dnl
+dnl * the GNU General Public License as published by the Free Software
+dnl Foundation; either version 2 of the License, or (at your option) any
+dnl later version.
+dnl
+dnl or both in parallel, as here.
+dnl
+dnl The GNU MP Library is distributed in the hope that it will be useful, but
+dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+dnl for more details.
+dnl
+dnl You should have received copies of the GNU General Public License and the
+dnl GNU Lesser General Public License along with the GNU MP Library. If not,
+dnl see https://www.gnu.org/licenses/.
+
+include(`../config.m4')
+
+C cycles/limb
+C 603e: ?
+C 604e: 5
+C 75x (G3): ?
+C 7400,7410 (G4): 8
+C 744x,745x (G4+): 6
+C power4/ppc970: 12
+C power5: ?
+
+C void mpn_divexact_by3 (mp_ptr dst, mp_srcptr src, mp_size_t size);
+C
+C We avoid the slow subfe instruction and instead rely on an extremely unlikely
+C branch.
+C
+C The mullw has the inverse in the first operand, since 0xAA..AB won't allow
+C any early-out. The src[] data normally won't either, but there's at least
+C a chance, whereas 0xAA..AB never will. If, for instance, src[] is all
+C zeros (not a sensible input of course) we run at 7.0 c/l on ppc750.
+C
+C The mulhwu has the "3" multiplier in the second operand, which lets 750 and
+C 7400 use an early-out.
+
+C INPUT PARAMETERS
+define(`rp', `r3')
+define(`up', `r4')
+define(`n', `r5')
+define(`cy', `r6')
+
+ASM_START()
+PROLOGUE(mpn_divexact_by3c)
+ lwz r11, 0(up)
+ mtctr n
+ lis r12, 0xAAAA
+ ori r12, r12, 0xAAAB
+ li r10, 3
+
+ cmplw cr7, cy, r11
+ subf r11, cy, r11
+
+ mullw r0, r11, r12
+ stw r0, 0(rp)
+ bdz L(one)
+
+L(top): lwzu r9, 4(up)
+ mulhwu r7, r0, r10
+ bgt- cr7, L(adj) C very unlikely branch
+L(bko): cmplw cr7, r7, r9
+ subf r0, r7, r9
+ mullw r0, r12, r0
+ stwu r0, 4(rp)
+ bdnz L(top)
+
+L(one): mulhwu r3, r0, r10
+ blelr+ cr7
+ addi r3, r3, 1
+ blr
+
+L(adj): addi r7, r7, 1
+ b L(bko)
+EPILOGUE()
+ASM_END()