[PATCH 2/3] bsps/i386: use Pentimum instructions for pc586 and pc686 builds.

[pisa at cmp.felk.cvut.cz]

From: Pavel Pisa <pisa at cmp.felk.cvut.cz>

When GCC option -march is not specifies i386-rtems toolchain
defaults to i386 architecture instruction set. It does not
provide atomic instructions which results in really inefficient
atomic_fetch_or even on UP build.

SMP build is broken with i386 set because libatomic and GCC
generate infinite loop for __atomic_fetch_add_4 used
in rtems_interrupt_lock_acquire

__atomic_fetch_add_4:
    push   %ebp
    mov    %esp,%ebp
    movl   $0x5,0x10(%ebp)
    pop    %ebp
    jmp    __atomic_fetch_add_4
---
 c/src/lib/libbsp/i386/pc386/make/custom/pc586.cfg | 2 +-
 c/src/lib/libbsp/i386/pc386/make/custom/pc686.cfg | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/c/src/lib/libbsp/i386/pc386/make/custom/pc586.cfg b/c/src/lib/libbsp/i386/pc386/make/custom/pc586.cfg
index 73e42cd..6f9cfcb 100644
--- a/c/src/lib/libbsp/i386/pc386/make/custom/pc586.cfg
+++ b/c/src/lib/libbsp/i386/pc386/make/custom/pc586.cfg
@@ -6,7 +6,7 @@ RTEMS_CPU_MODEL=pentium
 
 #  This contains the compiler options necessary to select the CPU model
 #  and (hopefully) optimize for it.
-CPU_CFLAGS = -mtune=pentium
+CPU_CFLAGS = -mtune=pentium -march=pentium
 
 include $(RTEMS_ROOT)/make/custom/pc386.cfg
 
diff --git a/c/src/lib/libbsp/i386/pc386/make/custom/pc686.cfg b/c/src/lib/libbsp/i386/pc386/make/custom/pc686.cfg
index 04f001f..b27e8ae 100644
--- a/c/src/lib/libbsp/i386/pc386/make/custom/pc686.cfg
+++ b/c/src/lib/libbsp/i386/pc386/make/custom/pc686.cfg
@@ -6,7 +6,7 @@ RTEMS_CPU_MODEL=pentiumpro
 
 #  This contains the compiler options necessary to select the CPU model
 #  and (hopefully) optimize for it.
-CPU_CFLAGS = -mtune=pentiumpro
+CPU_CFLAGS = -mtune=pentiumpro -march=pentium
 
 include $(RTEMS_ROOT)/make/custom/pc386.cfg
 
-- 
1.9.1