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Martin Storsjö 023ddc4128 Cygwin: crt: Add "volatile" to all inline assembly snippets under math
On 32 bit x86, clang seems to miss loading input parameters based
on asm constraints for inline assembly that uses the x87 floating
registers, unless the snippet has got the volatile keyword.

Signed-off-by: Martin Storsjö <martin@martin.st>
2020-08-30 14:27:43 +02:00

29 lines
713 B
C

/**
* This file has no copyright assigned and is placed in the Public Domain.
* This file is part of the mingw-w64 runtime package.
* No warranty is given; refer to the file DISCLAIMER.PD within this package.
*/
/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
* Adapted for long double type by Danny Smith <dannysmith@users.sourceforge.net>.
*/
/* asin = atan (x / sqrt(1 - x^2)) */
long double asinl (long double x);
long double asinl (long double x)
{
long double res = 0.0L;
asm volatile (
"fld %%st\n\t"
"fmul %%st(0)\n\t" /* x^2 */
"fld1\n\t"
"fsubp\n\t" /* 1 - x^2 */
"fsqrt\n\t" /* sqrt (1 - x^2) */
"fpatan"
: "=t" (res) : "0" (x) : "st(1)");
return res;
}