Support for 64-bit architectures: x86 in 64-bit mode

This commit enriches the IA32 port so that it supports x86 processors in 64-bit mode as well as in 32-bit mode, depending on the value of Archi.ptr64, which itself is set from the configuration model.

To activate x86-64 bit support, configure with "x86_64-linux".

Main steps:
- Enrich Op.v and Asm.v with 64-bit operations
- SelectLong: in 64-bit mode, use 64-bit operations directly; in 32-bit mode, fall back on the old implementation based on pairs of 32-bit integers
- Conventions1: support x86-64 ABI in addition to the 32-bit ABI.
- Add support for the new 64-bit operations everywhere.
- runtime/x86_64: implementation of the supporting library appropriate for x86 in 64-bit mode

To do:
- More optimizations are possible on 64-bit integer arithmetic operations.
- Could add new chunks to load, say, an unsigned byte into a 64-bit long
  (currently we load as a 32-bit int then zero-extend).
- Implements the wrong ABI for struct passing.

1 files changed, 13 insertions, 0 deletions

diff --git a/runtime/Makefile b/runtime/Makefile
index c01ef38d..59d2bb64 100644
--- a/runtime/Makefile
+++ b/runtime/Makefile
@@ -1,11 +1,24 @@
 include ../Makefile.config
 
 CFLAGS=-O1 -g -Wall
+
+ifeq ($(ARCH),ia32)
+ifeq ($(MODEL),64)
+ARCH=x86_64
+endif
+endif
+
+ifeq ($(ARCH),x86_64)
+OBJS=i64_dtou.o i64_utod.o i64_utof.o vararg.o
+else
 OBJS=i64_dtos.o i64_dtou.o i64_sar.o i64_sdiv.o i64_shl.o \
   i64_shr.o i64_smod.o i64_stod.o i64_stof.o \
   i64_udivmod.o i64_udiv.o i64_umod.o i64_utod.o i64_utof.o \
   vararg.o
+endif
+
 LIB=libcompcert.a
+
 INCLUDES=include/float.h include/stdarg.h include/stdbool.h \
   include/stddef.h include/varargs.h include/stdalign.h \
   include/stdnoreturn.h