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cosmopolitan/libc/intrin/bsr.h

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Initial import
2020-06-15 14:18:57 +00:00
#ifndef COSMOPOLITAN_LIBC_NEXGEN32E_BSR_H_
#define COSMOPOLITAN_LIBC_NEXGEN32E_BSR_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
Pay off more technical debt This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
2022-09-13 06:10:38 +00:00
int _bsr(int) pureconst;
int _bsrl(long) pureconst;
int _bsrll(long long) pureconst;
Add x86_64-linux-gnu emulator I wanted a tiny scriptable meltdown proof way to run userspace programs and visualize how program execution impacts memory. It helps to explain how things like Actually Portable Executable works. It can show you how the GCC generated code is going about manipulating matrices and more. I didn't feel fully comfortable with Qemu and Bochs because I'm not smart enough to understand them. I wanted something like gVisor but with much stronger levels of assurances. I wanted a single binary that'll run, on all major operating systems with an embedded GPL barrier ZIP filesystem that is tiny enough to transpile to JavaScript and run in browsers too. https://justine.storage.googleapis.com/emulator625.mp4
2020-08-25 11:23:25 +00:00
Make progress towards aarch64 build
2023-05-02 02:43:59 +00:00
#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
#ifdef __x86_64__
Pay off more technical debt This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
2022-09-13 06:10:38 +00:00
int _bsr128(uint128_t) pureconst;
#define _bsr(u) \
Improve performance of bitscanning intrinsics This change helps spectre more intelligently plan execution, by working around false output dependencies, impacting ops like popcnt bsr and bsf
2021-06-15 13:24:46 +00:00
({ \
unsigned BiTs; \
asm("bsr\t%0,%0" : "=r"(BiTs) : "0"((unsigned)(u)) : "cc"); \
BiTs; \
})
Pay off more technical debt This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
2022-09-13 06:10:38 +00:00
#define _bsrl(u) \
Improve performance of bitscanning intrinsics This change helps spectre more intelligently plan execution, by working around false output dependencies, impacting ops like popcnt bsr and bsf
2021-06-15 13:24:46 +00:00
({ \
unsigned long BiTs; \
asm("bsr\t%0,%0" : "=r"(BiTs) : "0"((unsigned long)(u)) : "cc"); \
(unsigned)BiTs; \
})
Pay off more technical debt This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
2022-09-13 06:10:38 +00:00
#define _bsrll(u) _bsrl(u)
Make progress towards aarch64 build
2023-05-02 02:43:59 +00:00
#else
#define _bsr(x) (__builtin_clz(x) ^ (sizeof(int) * CHAR_BIT - 1))
#define _bsrl(x) (__builtin_clzl(x) ^ (sizeof(long) * CHAR_BIT - 1))
#define _bsrll(x) (__builtin_clzll(x) ^ (sizeof(long long) * CHAR_BIT - 1))
#endif
Add chibicc This program popped up on Hacker News recently. It's the only modern compiler I've ever seen that doesn't have dependencies and is easily modified. So I added all of the missing GNU extensions I like to use which means it might be possible soon to build on non-Linux and have third party not vendor gcc binaries.
2020-12-05 20:20:41 +00:00
#endif
Initial import
2020-06-15 14:18:57 +00:00
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_NEXGEN32E_BSR_H_ */
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