From 4f75515cd3bfe8360e9c5621641c852e0bd0230f Mon Sep 17 00:00:00 2001 From: Tim Allen Date: Sat, 9 Jan 2021 01:25:00 +1100 Subject: [PATCH] doc: Add example programs using libco. These examples were originally included in various standalone libco releases, not as part of any higan or bsnes release. test_timing in particular is a benchmark and smoke-test as well as a basic example of how to use libco. --- doc/examples/.gitignore | 4 + doc/examples/build.bat | 8 ++ doc/examples/build.sh | 8 ++ doc/examples/test.h | 6 ++ doc/examples/test_args.cpp | 76 +++++++++++++++++++ doc/examples/test_serialization.cpp | 112 ++++++++++++++++++++++++++++ doc/examples/test_timing.cpp | 52 +++++++++++++ 7 files changed, 266 insertions(+) create mode 100644 doc/examples/.gitignore create mode 100755 doc/examples/build.bat create mode 100755 doc/examples/build.sh create mode 100644 doc/examples/test.h create mode 100644 doc/examples/test_args.cpp create mode 100644 doc/examples/test_serialization.cpp create mode 100644 doc/examples/test_timing.cpp diff --git a/doc/examples/.gitignore b/doc/examples/.gitignore new file mode 100644 index 00000000..d3db2568 --- /dev/null +++ b/doc/examples/.gitignore @@ -0,0 +1,4 @@ +test_args +test_serialization +test_timing +*.o diff --git a/doc/examples/build.bat b/doc/examples/build.bat new file mode 100755 index 00000000..f8fecb26 --- /dev/null +++ b/doc/examples/build.bat @@ -0,0 +1,8 @@ +cc -O3 -fomit-frame-pointer -I../.. -o libco.o -c ../../libco.c +c++ -O3 -fomit-frame-pointer -I../.. -c test_timing.cpp +c++ -O3 -fomit-frame-pointer -o test_timing libco.o test_timing.o +c++ -O3 -fomit-frame-pointer -I../.. -c test_args.cpp +c++ -O3 -fomit-frame-pointer -o test_args libco.o test_args.o +c++ -O3 -fomit-frame-pointer -I../.. -c test_serialization.cpp +c++ -O3 -fomit-frame-pointer -o test_serialization libco.o test_serialization.o +@del *.o diff --git a/doc/examples/build.sh b/doc/examples/build.sh new file mode 100755 index 00000000..dd187a99 --- /dev/null +++ b/doc/examples/build.sh @@ -0,0 +1,8 @@ +cc -O3 -fomit-frame-pointer -I../.. -o libco.o -c ../../libco.c +c++ -O3 -fomit-frame-pointer -I../.. -c test_timing.cpp +c++ -O3 -fomit-frame-pointer -o test_timing libco.o test_timing.o +c++ -O3 -fomit-frame-pointer -I../.. -c test_args.cpp +c++ -O3 -fomit-frame-pointer -o test_args libco.o test_args.o +c++ -O3 -fomit-frame-pointer -I../.. -c test_serialization.cpp +c++ -O3 -fomit-frame-pointer -o test_serialization libco.o test_serialization.o +rm -f *.o diff --git a/doc/examples/test.h b/doc/examples/test.h new file mode 100644 index 00000000..753ea52f --- /dev/null +++ b/doc/examples/test.h @@ -0,0 +1,6 @@ +#include +#include +#include +#include + +#include diff --git a/doc/examples/test_args.cpp b/doc/examples/test_args.cpp new file mode 100644 index 00000000..1e6e2bbb --- /dev/null +++ b/doc/examples/test_args.cpp @@ -0,0 +1,76 @@ +/***** + * cothread parameterized function example + ***** + * entry point to cothreads cannot take arguments. + * this is due to portability issues: each processor, + * operating system, programming language and compiler + * can use different parameter passing methods, so + * arguments to the cothread entry points were omitted. + * + * however, the behavior can easily be simulated by use + * of a specialized co_switch to set global parameters to + * be used as function arguments. + * + * in this way, with a bit of extra red tape, one gains + * even more flexibility than would be possible with a + * fixed argument list entry point, such as void (*)(void*), + * as any number of arguments can be used. + * + * this also eliminates race conditions where a pointer + * passed to co_create may have changed or become invalidated + * before call to co_switch, as said pointer would now be set + * when calling co_switch, instead. + *****/ + +#include "test.h" + +cothread_t thread[3]; + +namespace co_arg { + int param_x; + int param_y; +}; + +//one could also call this co_init or somesuch if they preferred ... +void co_switch(cothread_t thread, int param_x, int param_y) { + co_arg::param_x = param_x; + co_arg::param_y = param_y; + co_switch(thread); +} + +void co_entrypoint() { +int param_x = co_arg::param_x; +int param_y = co_arg::param_y; + printf("co_entrypoint(%d, %d)\n", param_x, param_y); + co_switch(thread[0]); + +//co_arg::param_x will change here (due to co_switch(cothread_t, int, int) call changing values), +//however, param_x and param_y will persist as they are thread local + + printf("co_entrypoint(%d, %d)\n", param_x, param_y); + co_switch(thread[0]); + throw; +} + +int main() { + printf("cothread parameterized function example\n\n"); + + thread[0] = co_active(); + thread[1] = co_create(65536, co_entrypoint); + thread[2] = co_create(65536, co_entrypoint); + +//use specialized co_switch(cothread_t, int, int) for initial co_switch call + co_switch(thread[1], 1, 2); + co_switch(thread[2], 4, 8); + +//after first call, entry point arguments have been initialized, standard +//co_switch(cothread_t) can be used from now on + co_switch(thread[2]); + co_switch(thread[1]); + + printf("\ndone\n"); +#if defined(_MSC_VER) || defined(__DJGPP__) + getch(); +#endif + return 0; +} diff --git a/doc/examples/test_serialization.cpp b/doc/examples/test_serialization.cpp new file mode 100644 index 00000000..b690d862 --- /dev/null +++ b/doc/examples/test_serialization.cpp @@ -0,0 +1,112 @@ +#include "test.h" +#include +#include + +namespace Thread { + cothread_t host; + cothread_t cpu; + cothread_t apu; +} + +namespace Buffer { + uint8_t cpu[65536]; + uint8_t apu[65536]; +} + +namespace Memory { + uint8_t* buffer; +} + +struct CPU { + static auto Enter() -> void; + auto main() -> void; + auto sub() -> void; + auto leaf() -> void; +} cpu; + +struct APU { + static auto Enter() -> void; + auto main() -> void; + auto sub() -> void; + auto leaf() -> void; +} apu; + +auto CPU::Enter() -> void { + while(true) cpu.main(); +} + +auto CPU::main() -> void { + printf("2\n"); + sub(); +} + +auto CPU::sub() -> void { + co_switch(Thread::apu); + printf("4\n"); + leaf(); +} + +auto CPU::leaf() -> void { + int x = 42; + co_switch(Thread::host); + printf("6\n"); + co_switch(Thread::apu); + printf("8 (%d)\n", x); + co_switch(Thread::host); +} + +auto APU::Enter() -> void { + while(true) apu.main(); +} + +auto APU::main() -> void { + printf("3\n"); + sub(); +} + +auto APU::sub() -> void { + co_switch(Thread::cpu); + printf("7\n"); + leaf(); +} + +auto APU::leaf() -> void { + co_switch(Thread::cpu); +} + +auto main() -> int { + Memory::buffer = (uint8_t*)mmap( + (void*)0x10'0000'0000, 2 * 65536, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0 + ); + Memory::buffer[0] = 42; + printf("%p (%u)\n", Memory::buffer, Memory::buffer[0]); + + Thread::host = co_active(); + Thread::cpu = co_derive((void*)(Memory::buffer + 0 * 65536), 65536, CPU::Enter); + Thread::apu = co_derive((void*)(Memory::buffer + 1 * 65536), 65536, APU::Enter); + + printf("1\n"); + co_switch(Thread::cpu); + + printf("5\n"); + memcpy(Buffer::cpu, Thread::cpu, 65536); + memcpy(Buffer::apu, Thread::apu, 65536); + co_switch(Thread::cpu); + + Thread::cpu = nullptr; + Thread::apu = nullptr; + Thread::cpu = co_derive((void*)(Memory::buffer + 0 * 65536), 65536, CPU::Enter); + Thread::apu = co_derive((void*)(Memory::buffer + 1 * 65536), 65536, APU::Enter); + + printf("9\n"); + memcpy(Thread::cpu, Buffer::cpu, 65536); + memcpy(Thread::apu, Buffer::apu, 65536); + co_switch(Thread::cpu); + + Thread::cpu = nullptr; + Thread::apu = nullptr; + munmap((void*)0x900000000, 2 * 65536); + return 0; +} diff --git a/doc/examples/test_timing.cpp b/doc/examples/test_timing.cpp new file mode 100644 index 00000000..0232e47e --- /dev/null +++ b/doc/examples/test_timing.cpp @@ -0,0 +1,52 @@ +#include "test.h" +enum { Iterations = 500000000 }; + +namespace thread { + cothread_t x; + cothread_t y; + volatile int counter; +} + +void co_timingtest() { + for(;;) { + thread::counter++; + co_switch(thread::x); + } +} + +void sub_timingtest() { + thread::counter++; +} + +int main() { + printf("context-switching timing test\n\n"); + time_t start, end; + int i, t1, t2; + + start = clock(); + for(thread::counter = 0, i = 0; i < Iterations; i++) { + sub_timingtest(); + } + end = clock(); + + t1 = (int)difftime(end, start); + printf("%2.3f seconds per 50 million subroutine calls (%d iterations)\n", (float)t1 / CLOCKS_PER_SEC, thread::counter); + + thread::x = co_active(); + thread::y = co_create(65536, co_timingtest); + + start = clock(); + for(thread::counter = 0, i = 0; i < Iterations; i++) { + co_switch(thread::y); + } + end = clock(); + + co_delete(thread::y); + + t2 = (int)difftime(end, start); + printf("%2.3f seconds per 100 million co_switch calls (%d iterations)\n", (float)t2 / CLOCKS_PER_SEC, thread::counter); + + printf("co_switch skew = %fx\n\n", (double)t2 / (double)t1); + return 0; +} +