Remove 5x64 implementation - no actual benefits

Makefile

@@ -8,7 +8,7 @@ JAVA_FILES := src/java/org_bitcoin_NativeSecp256k1.h src/java/org_bitcoin_Native
 OBJS :=
 
 ifeq ($(USE_ASM), 1)
-    OBJS := $(OBJS) obj/field_5x$(HAVE_LIMB)_asm.o
+    OBJS := $(OBJS) obj/field_5x52_asm.o
 endif
 STD="gnu99"
 
@@ -20,9 +20,6 @@ clean:
 obj/field_5x52_asm.o: src/field_5x52_asm.asm
 	$(YASM) -f elf64 -o obj/field_5x52_asm.o src/field_5x52_asm.asm
 
-obj/field_5x64_asm.o: src/field_5x64_asm.asm
-	$(YASM) -f elf64 -o obj/field_5x64_asm.o src/field_5x64_asm.asm
-
 obj/secp256k1.o: $(FILES) src/secp256k1.c include/secp256k1.h
 	$(CC) -fPIC -std=$(STD) $(CFLAGS) $(CFLAGS_EXTRA) -DNDEBUG -$(OPTLEVEL) src/secp256k1.c -c -o obj/secp256k1.o
 

configure

@@ -97,9 +97,6 @@ if [ "$?" = 0 ]; then
     HAVE_INT128=1
 fi
 
-#default limb size
-HAVE_LIMB=52
-
 for arg in "$@"; do
     case "$arg" in
         --no-yasm)
@@ -110,9 +107,6 @@ for arg in "$@"; do
             ;;
         --no-openssl)
             HAVE_OPENSSL=0
-	    ;;
-	--use-5x64)
-	    HAVE_LIMB=64
             ;;
         --use-endomorphism)
             USE_ENDOMORPHISM=1
@@ -126,10 +120,10 @@ USE_ASM=0
 
 # select field implementation
 if [ "$HAVE_YASM" = "1" ]; then
-    CFLAGS_FIELD="-DUSE_FIELD_5X$HAVE_LIMB -DUSE_FIELD_5X${HAVE_LIMB}_ASM"
+    CFLAGS_FIELD="-DUSE_FIELD_5X52 -DUSE_FIELD_5X52_ASM"
     USE_ASM=1
 elif [ "$HAVE_INT128" = "1" ]; then
-    CFLAGS_FIELD="-DUSE_FIELD_5X$HAVE_LIMB -DUSE_FIELD_5X${HAVE_LIMB}_INT128"
+    CFLAGS_FIELD="-DUSE_FIELD_5X52 -DUSE_FIELD_5X52_INT128"
 elif [ "$HAVE_GMP" = "1" ]; then
     CFLAGS_FIELD="-DUSE_FIELD_GMP"
     LINK_GMP=1
@@ -176,5 +170,4 @@ echo "CFLAGS_TEST_EXTRA=$CFLAGS_TEST_EXTRA" >> config.mk
 echo "LDFLAGS_EXTRA=$LDFLAGS_EXTRA" >> config.mk
 echo "LDFLAGS_TEST_EXTRA=$LDFLAGS_TEST_EXTRA" >> config.mk
 echo "USE_ASM=$USE_ASM" >>config.mk
-echo "HAVE_LIMB=$HAVE_LIMB" >>config.mk
 echo "OPTLEVEL=O2" >>config.mk

src/field.h

@@ -22,8 +22,6 @@
 #include "field_10x26.h"
 #elif defined(USE_FIELD_5X52)
 #include "field_5x52.h"
-#elif defined(USE_FIELD_5X64)
-#include "field_5x64.h"
 #else
 #error "Please select field implementation"
 #endif