powerpc

I followed these instructions on how to get the 10.4 SDK working with PPC after upgrading to XCode 4. I am able to compile, but it errors out at link time. As an added wrinkle, I'm not using XCode per se, but the gcc toolchain that comes with it. (This is part of a large cross-platform project that uses makefiles.) Here's a sample makefile: CXX=g++-4.0 CXXFLAGS=-arch i386 -arch ppc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -mmacosx-version-min=10.4 helloworld: helloworld.o $(CXX) $^ -o $@ $(CXXFLAGS) with a helloworld.cpp: #include <stdio.h> int main(void) { printf("hello world \n"); return 0;

I have a Lion (10.7.1) system on which I installed Xcode 4.2. Suppose I have a simple C program helloWorld.c as follows: #include <stdio.h> main() { printf("hello, world\n"); } Using this setup, I would like to try to compile helloWorld.c for use on PPC and PPC64 architectures, e.g. : $ gcc -arch ppc helloWorld.c -o helloWorld This gives the following error message: llvm-gcc-4.2: error trying to exec '/usr/bin/../llvm-gcc-4.2/bin/powerpc-apple-darwin11-llvm-gcc-4.2': execvp: No such file or directory How do I restore support for PowerPC to my Xcode 4 installation? I have tried the instructions

As known, PowerPC has weak memory model, that permit any speculative reordering: Store-Store, Load-Store, Store-Load, Load-Load. There are at least 3 Fences: hwsync or sync - full memory barrier, prevents any reordering lwsync - memory barriers that prevents reordering: Load-Load, Store-Store, Load-Store isync - instruction barrier : https://www.ibm.com/support/knowledgecenter/en/ssw_aix_71/com.ibm.aix.alangref/idalangref_isync_ics_instrs.htm For example, can be reordered Store- stwcx. and Load- lwz in this code?: https://godbolt.org/g/84t5jM lwarx 9,0,10 addi 9,9,2 stwcx. 9,0,10 bne- 0,.L2

On Darwin, the POSIX standard clock_gettime(CLOCK_MONOTONIC) timer is not available. Instead, the highest resolution monotonic timer is obtained through the mach_absolute_time function from mach/mach_time.h . The result returned may be an unadjusted tick count from the processor, in which case the time units could be a strange multiple. For example, on a CPU with a 33MHz tick count, Darwin returns 1000000000/33333335 as the exact units of the returned result (ie, multiply the mach_absolute_time by that fraction to obtain a nanosecond value). We usually wish to convert from exact ticks to

I'm trying to find a way to perform an indirect shift-left/right operation without actually using the variable shift op or any branches. The particular PowerPC processor I'm working on has the quirk that a shift-by-constant-immediate, like int ShiftByConstant( int x ) { return x << 3 ; } is fast, single-op, and superscalar, whereas a shift-by-variable, like int ShiftByVar( int x, int y ) { return x << y ; } is a microcoded operation that takes 7-11 cycles to execute while the entire rest of the pipeline stops dead . What I'd like to do is figure out which non-microcoded integer PPC ops the