kolibrios/programs/develop/ktcc/trunk/libc/math/acos.asm
siemargl af35cc6783 release ktcc 0.9.26
git-svn-id: svn://kolibrios.org@6424 a494cfbc-eb01-0410-851d-a64ba20cac60
2016-05-11 14:53:54 +00:00

24 lines
579 B
NASM

format ELF
include 'proc32.inc'
section '.text' executable
public acos_ as "acos"
acos_:
; acos(x) = atan(sqrt((1-x*x)/(x*x)))
fld qword[esp+4]
fld st0 ;Duplicate X on tos.
fmul st0, st1 ;Compute X**2.
fld st0 ;Duplicate X**2 on tos.
fld1 ;Compute 1-X**2.
fsub st0, st1
fdiv st0, st1 ;Compute (1-x**2)/X**2.
fsqrt ;Compute sqrt((1-X**2)/X**2).
fld1 ;To compute full arctangent.
fpatan ;Compute atan of the above.
ret