2016-04-18 Thomas Preud'homme <thomas.preudhomme@arm.com>
* libc/machine/arm/strlen-stub.c: Check capabilities of architecture
to decide which Thumb implementation to use and fall back to C
implementation for architecture not supporting Thumb mode.
* libc/machine/arm/strlen.S: Likewise.
Reformulate the strcmp-armv7.S selection logic around the architecture
features required by the implementation code rather (some) version of
the architecture that expose those features.
The patch moves the inline ASM thumb2 -Os implementation out into its
own .S file.
Tested by building newlib and comparing libc.a binaries before and
after for all permutations of:
Architectures:
armv4 armv4t armv5 armv5t armv5te armv6 armv6j armv6k
armv6z armv6kz armv6t2 armv6-m armv6s-m armv7 armv7-a
armv7ve armv7-r armv7-m armv7e-m armv8-a iwmmxt iwmmxt2
ISAs:
thumb arm
Optimization Levels:
Os O2
Excluding:
armv6s-m -mthumb
armv6-m -mthumb
armv6zk -mthumb
armv6z -mthumb
armv6k -mthumb
armv6j -mthumb
The patch moves the inline ASM thumb1 -O2 implementation out into its
own .S file.
Tested by building newlib and comparing libc.a binaries before and
after for all permutations of:
Architectures:
armv4 armv4t armv5 armv5t armv5te armv6 armv6j armv6k
armv6z armv6kz armv6t2 armv6-m armv6s-m armv7 armv7-a
armv7ve armv7-r armv7-m armv7e-m armv8-a iwmmxt iwmmxt2
ISAs:
thumb arm
Optimization Levels:
Os O2
Excluding:
armv6s-m -mthumb
armv6-m -mthumb
armv6zk -mthumb
armv6z -mthumb
armv6k -mthumb
armv6j -mthumb
The patch adds strlen.S to contain the complementary preprocessor
logic to strlen-stub.c intended to provide #inclusion of alternative
.S implementations.
Initially we just include the existing strlen-armv7.S implementation.
We rewrite _ISA_ARMV7 in both strlen.S and strlen-stub.c to use the
underlying existing underlying defintion from arm_asm.h in order to
avoide including that file, this is in effect the first step towards a
move to ACLE predefines only.
Tested by building newlib and comparing libc.a binaries before and
after for all permutations of:
Architectures:
armv4 armv4t armv5 armv5t armv5te armv6 armv6j armv6k
armv6z armv6kz armv6t2 armv6-m armv6s-m armv7 armv7-a
armv7ve armv7-r armv7-m armv7e-m armv8-a iwmmxt iwmmxt2
ISAs:
thumb arm
Optimization Levels:
Os O2
Excluding:
armv6s-m -mthumb
armv6-m -mthumb
armv6zk -mthumb
armv6z -mthumb
armv6k -mthumb
armv6j -mthumb
Jeff Johnston
Marcus Shawcroft