Basic support for software threads.
Missed a file
Add boilerplate
Simple ready queue for fibers.
This is inefficient due to contention for the ready queue lock.
Now that the calling convention is fixed in the compiler, I can clean
up the global intializer code in start.s
Merge branch 'master' of github.com:jbush001/GPGPU
Modify code to adapt to ABI change.  The number of callee saved registers
has been reduced, which makes context switches less expensive.
Rearrange Fiber class.
Default to phong shading
Make threading core aware
Make Barrier use constants for number of threads (instead of template)
Add memory barrier to synchronization primitives
Add tests for __sync_bool_compare_and_swap and __sync_val_compare_and_swap
Remove usage of -integrated-as flag, which is now default
No longer need to specify target type
Fix some Verilator warnings
Cleanup
Comment update
Change optimization level for verilator to -O1.  This compiles
about 5x as fast as -O3 and only runs about 40% slower.
Turn on full optimization for instruction set simulator.