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2020-08-12setjmp: optimize longjmp prologuesAlexander Monakov-5/+3
Use a branchless sequence that is one byte shorter on 64-bit, same size on 32-bit. Thanks to Pete Cawley for suggesting this variant.
2020-08-11setjmp: optimize x86 longjmp epiloguesAlexander Monakov-4/+2
2020-08-11setjmp: avoid useless REX-prefix on xor %eax, %eaxAlexander Monakov-1/+1
2020-08-11setjmp: fix x86-64 longjmp argument adjustmentAlexander Monakov-3/+3
longjmp 'val' argument is an int, but the assembly is referencing 64-bit registers as if the argument was a long, or the caller was responsible for extending the argument. Though the psABI is not clear on this, the interpretation in GCC is that high bits may be arbitrary and the callee is responsible for sign/zero-extending the value as needed (likewise for return values: callers must anticipate that high bits may be garbage). Therefore testing %rax is a functional bug: setjmp would wrongly return zero if longjmp was called with val==0, but high bits of %rsi happened to be non-zero. Rewrite the prologue to refer to 32-bit registers. In passing, change 'test' to use %rsi, as there's no advantage to using %rax and the new form is cheaper on processors that do not perform move elimination.
2012-05-05update license of njk contributed code (x86_64 asm)Rich Felker-2/+2
these changes are based on the following communication via email: "I hereby grant that all of the code I have contributed to musl on or before April 23, 2012 may be licensed under the terms of the following MIT license: Copyright (c) 2011-2012 Nicholas J. Kain Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE."
2011-06-14restore use of .type in asm, but use modern @function (vs %function)Rich Felker-0/+5
this seems to be necessary to make the linker accept the functions in a shared library (perhaps to generate PLT entries?) strictly speaking libc-internal asm should not need it. i might clean that up later.
2011-06-13remove all .size and .type directives for functions from the asmRich Felker-10/+0
these are useless and have caused problems for users trying to build with non-gnu tools like tcc's assembler.
2011-05-26modernize coding style in sjlj asmRich Felker-12/+12
2011-02-15Port musl to x86-64. One giant commit!Nicholas J. Kain-0/+49