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https://github.com/jart/cosmopolitan.git
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5c6877b02b
The feenableexcept() and fedisableexcept() APIs are now provided which let you detect when NaNs appear the moment it happens from anywhere in your program. Tests have also been added for the mission critical math functions expf() and erff(), whose perfect operation has been assured. See examples/trapping.c to see how to use this powerful functionality.
159 lines
5.2 KiB
ArmAsm
159 lines
5.2 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│ vi: set noet ft=asm ts=8 sw=8 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/macros.internal.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/dce.h"
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#ifdef __x86_64__
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.text.startup
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// Cosmopolitan runtime.
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//
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// @param edi is argc
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// @param rsi is argv
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// @param rdx is environ
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// @param rcx is auxv
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// @noreturn
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cosmo: push %rbp
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mov %rsp,%rbp
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mov %edi,%r12d
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mov %rsi,%r13
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mov %rdx,%r14
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mov %rcx,%r15
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#if SYSDEBUG
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call __strace_init
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mov %eax,%r12d
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#endif /* SYSDEBUG */
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#ifndef NOX87
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// Windows always initializes FPU to douuble precision.
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// WSL breaks Linux ABI by initializing FPU to double precision.
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// This code makes long double long again.
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//
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// @see System V Application Binary Interface NexGen32e Architecture
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// Processor Supplement, Version 1.0, December 5th, 2018
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// Section 3.4.1: Initial Stack and Register State
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fldcw 1f(%rip)
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.rodata
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.balign 2
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// 8087 FPU Control Word
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// IM: Invalid Operation ───────────────┐
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// DM: Denormal Operand ───────────────┐│
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// ZM: Zero Divide ───────────────────┐││
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// OM: Overflow ─────────────────────┐│││
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// UM: Underflow ───────────────────┐││││
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// PM: Precision ──────────────────┐│││││
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// PC: Precision Control ───────┐ ││││││
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// {float,∅,double,long double}│ ││││││
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// RC: Rounding Control ──────┐ │ ││││││
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// {even, →-∞, →+∞, →0} │┌┤ ││││││
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// ┌┤││ ││││││
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// d││││rr││││││
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1: .short 0b00000000000000000001101111111
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.previous
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#endif
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#ifdef __FAST_MATH__
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push %rax
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stmxcsr (%rsp)
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//
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// Enable hardware optimizations in violation of the IEEE standard.
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//
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// - 0x0040 enables "DAZ: Denormals Are Zeros" in MXCSR. This causes the
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// processor to turn denormal inputs into zero, before computing them.
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// See Intel Manual Vol. 1 §10.2.3.4
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//
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// - 0x8000 enables "FTZ: Flush To Zero" in MXCSR. This means a floating
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// point operation that results in underflow will be set to zero, with
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// the same sign, rather than producing a denormalized output. It will
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// happen only if underflow trapping hasnt been enabled. See the Intel
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// Manual Vol. 1 §10.2.3.3.
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//
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orl $0x8040,(%rsp)
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ldmxcsr (%rsp)
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pop %rax
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#endif
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// run assembly init
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call _init
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// call constructors
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.weak __init_array_end
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.weak __init_array_start
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mov $__init_array_start,%eax
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1: cmp $__init_array_end,%eax
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je 2f
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push %rax
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push %rax
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call .Largs
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call *(%rax)
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pop %rax
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pop %rax
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add $8,%eax
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jmp 1b
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// call main()
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2: call .Largs
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.weak main
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call main
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xchg %eax,%edi
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call exit
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.Largs: mov %r12d,%edi
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mov %r13,%rsi
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mov %r14,%rdx
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mov %r15,%rcx
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ret
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.endfn cosmo,weak
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// Enables Thread Local Storage.
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.init.start 304,_init_tls
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push %rdi
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push %rsi
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call __enable_tls
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pop %rsi
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pop %rdi
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.init.end 304,_init_tls
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#if IsAsan()
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.init.start 305,_init_symbols
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push %rdi
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push %rsi
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call __init_symbols
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pop %rsi
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pop %rdi
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.init.end 305,_init_symbols
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#endif
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#ifdef FTRACE
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.init.start 306,_init_ftrace
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push %rdi
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push %rsi
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call ftrace_init
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mov %eax,%r12d
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pop %rsi
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pop %rdi
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.init.end 306,_init_ftrace
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#endif
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#endif /* __x86_64__ */
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