From 797c960d2004eacbbd19c656f483f070130bb358 Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Fri, 6 Apr 2012 11:37:07 +0200 Subject: [PATCH] Rewrite pop_1st_bit() to be endian independent With this change sources are fully endianess independent, so we can simplify the Makefile. Somewhat surprisingly we don't have any speed regression ! No functional change. Signed-off-by: Marco Costalba --- src/Makefile | 50 +++++------------------------------------------- src/bitboard.cpp | 30 +++++------------------------ 2 files changed, 10 insertions(+), 70 deletions(-) diff --git a/src/Makefile b/src/Makefile index a4350665..eba72150 100644 --- a/src/Makefile +++ b/src/Makefile @@ -47,7 +47,6 @@ OBJS = benchmark.o bitbase.o bitboard.o book.o endgame.o evaluate.o main.o \ # arch = (name) --- (-arch) --- Target architecture # os = (name) --- --- Target operating system # bits = 64/32 --- -DIS_64BIT --- 64-/32-bit operating system -# bigendian = yes/no --- -DBIGENDIAN --- big/little-endian byte order # prefetch = yes/no --- -DUSE_PREFETCH --- Use prefetch x86 asm-instruction # bsfq = yes/no --- -DUSE_BSFQ --- Use bsfq x86_64 asm-instruction (only # with GCC and ICC 64-bit) @@ -68,7 +67,6 @@ ifeq ($(ARCH),general-64) arch = any os = any bits = 64 - bigendian = no prefetch = no bsfq = no popcnt = no @@ -78,27 +76,6 @@ ifeq ($(ARCH),general-32) arch = any os = any bits = 32 - bigendian = no - prefetch = no - bsfq = no - popcnt = no -endif - -ifeq ($(ARCH),bigendian-64) - arch = any - os = any - bits = 64 - bigendian = yes - prefetch = no - bsfq = no - popcnt = no -endif - -ifeq ($(ARCH),bigendian-32) - arch = any - os = any - bits = 32 - bigendian = yes prefetch = no bsfq = no popcnt = no @@ -109,7 +86,6 @@ ifeq ($(ARCH),x86-64) arch = x86_64 os = any bits = 64 - bigendian = no prefetch = yes bsfq = yes popcnt = no @@ -119,7 +95,6 @@ ifeq ($(ARCH),x86-64-modern) arch = x86_64 os = any bits = 64 - bigendian = no prefetch = yes bsfq = yes popcnt = yes @@ -129,7 +104,6 @@ ifeq ($(ARCH),x86-32) arch = i386 os = any bits = 32 - bigendian = no prefetch = yes bsfq = no popcnt = no @@ -139,7 +113,6 @@ ifeq ($(ARCH),x86-32-old) arch = i386 os = any bits = 32 - bigendian = no prefetch = no bsfq = no popcnt = no @@ -150,7 +123,6 @@ ifeq ($(ARCH),osx-ppc-64) arch = ppc64 os = osx bits = 64 - bigendian = yes prefetch = no bsfq = no popcnt = no @@ -160,7 +132,6 @@ ifeq ($(ARCH),osx-ppc-32) arch = ppc os = osx bits = 32 - bigendian = yes prefetch = no bsfq = no popcnt = no @@ -170,7 +141,6 @@ ifeq ($(ARCH),osx-x86-64) arch = x86_64 os = osx bits = 64 - bigendian = no prefetch = yes bsfq = yes popcnt = no @@ -180,7 +150,6 @@ ifeq ($(ARCH),osx-x86-32) arch = i386 os = osx bits = 32 - bigendian = no prefetch = yes bsfq = no popcnt = no @@ -293,12 +262,7 @@ ifeq ($(bits),64) CXXFLAGS += -DIS_64BIT endif -### 3.7 Endianess -ifeq ($(bigendian),yes) - CXXFLAGS += -DBIGENDIAN -endif - -### 3.8 prefetch +### 3.7 prefetch ifeq ($(prefetch),yes) CXXFLAGS += -msse DEPENDFLAGS += -msse @@ -306,17 +270,17 @@ else CXXFLAGS += -DNO_PREFETCH endif -### 3.9 bsfq +### 3.8 bsfq ifeq ($(bsfq),yes) CXXFLAGS += -DUSE_BSFQ endif -### 3.10 popcnt +### 3.9 popcnt ifeq ($(popcnt),yes) CXXFLAGS += -msse3 -DUSE_POPCNT endif -### 3.11 Link Time Optimization, it works since gcc 4.5 but not on mingw. +### 3.10 Link Time Optimization, it works since gcc 4.5 but not on mingw. ### This is a mix of compile and link time options because the lto link phase ### needs access to the optimization flags. ifeq ($(comp),gcc) @@ -359,8 +323,6 @@ help: @echo "osx-x86-32 > x86-Mac OS X 32 bit" @echo "general-64 > unspecified 64-bit" @echo "general-32 > unspecified 32-bit" - @echo "bigendian-64 > unspecified 64-bit with bigendian byte order" - @echo "bigendian-32 > unspecified 32-bit with bigendian byte order" @echo "" @echo "Supported comps:" @echo "" @@ -433,7 +395,6 @@ config-sanity: @echo "arch: '$(arch)'" @echo "os: '$(os)'" @echo "bits: '$(bits)'" - @echo "bigendian: '$(bigendian)'" @echo "prefetch: '$(prefetch)'" @echo "bsfq: '$(bsfq)'" @echo "popcnt: '$(popcnt)'" @@ -451,7 +412,6 @@ config-sanity: test "$(arch)" = "ppc64" || test "$(arch)" = "ppc" @test "$(os)" = "any" || test "$(os)" = "osx" @test "$(bits)" = "32" || test "$(bits)" = "64" - @test "$(bigendian)" = "yes" || test "$(bigendian)" = "no" @test "$(prefetch)" = "yes" || test "$(prefetch)" = "no" @test "$(bsfq)" = "yes" || test "$(bsfq)" = "no" @test "$(popcnt)" = "yes" || test "$(popcnt)" = "no" @@ -507,7 +467,7 @@ icc-profile-clean: hpux: $(MAKE) \ - CXX='/opt/aCC/bin/aCC -AA +hpxstd98 -DBIGENDIAN -mt +O3 -DNDEBUG -DNO_PREFETCH' \ + CXX='/opt/aCC/bin/aCC -AA +hpxstd98 -mt +O3 -DNDEBUG -DNO_PREFETCH' \ CXXFLAGS="" \ LDFLAGS="" \ all diff --git a/src/bitboard.cpp b/src/bitboard.cpp index 321055e8..40cdbb21 100644 --- a/src/bitboard.cpp +++ b/src/bitboard.cpp @@ -92,33 +92,13 @@ Square first_1(Bitboard b) { return Square(BSFTable[(fold * 0x783A9B23) >> 26]); } -// Use type-punning -union b_union { - - Bitboard dummy; - struct { -#if defined (BIGENDIAN) - uint32_t h; - uint32_t l; -#else - uint32_t l; - uint32_t h; -#endif - } b; -}; - Square pop_1st_bit(Bitboard* b) { - const b_union u = *((b_union*)b); - - if (u.b.l) - { - ((b_union*)b)->b.l = u.b.l & (u.b.l - 1); - return Square(BSFTable[((u.b.l ^ (u.b.l - 1)) * 0x783A9B23) >> 26]); - } - - ((b_union*)b)->b.h = u.b.h & (u.b.h - 1); - return Square(BSFTable[((~(u.b.h ^ (u.b.h - 1))) * 0x783A9B23) >> 26]); + Bitboard bb = *b; + *b = bb & (bb - 1); + bb ^= (bb - 1); + uint32_t fold = unsigned(bb) ^ unsigned(bb >> 32); + return Square(BSFTable[(fold * 0x783A9B23) >> 26]); } Square last_1(Bitboard b) { -- 2.39.2