161 lines
4.4 KiB
ArmAsm
161 lines
4.4 KiB
ArmAsm
/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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.data
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.align 2
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;_sccsid:
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;.asciz "from: @(#)support.s 5.2 (Berkeley) 5/17/90"
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_rcsid:
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.asciz "$Id: support.s,v 1.1 1993/08/14 13:43:45 mycroft Exp $"
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.text
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.globl _copysign, _finite, _scalb, _logb, _drem, _pow_p, _atan2__A
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| copysign(x,y)
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| returns x with the sign of y.
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_copysign:
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movl sp@(4),d0
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movl sp@(8),d1
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tstw sp@(12)
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jmi Lneg
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bclr #31,d0
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rts
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Lneg:
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bset #31,d0
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rts
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| finite(x)
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| returns the value TRUE if -INF < x < +INF and returns FALSE otherwise.
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_finite:
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movw #0x7FF0,d0
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movw sp@(4),d1
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andw d0,d1
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cmpw d0,d1
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beq Lnotfin
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moveq #1,d0
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rts
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Lnotfin:
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clrl d0
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rts
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| scalb(x, N)
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| returns x * (2**N), for integer values N.
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_scalb:
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fmoved sp@(4),fp0
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fbeq Ldone
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fscalel sp@(12),fp0
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Ldone:
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fmoved fp0,sp@-
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movel sp@+,d0
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movel sp@+,d1
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rts
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| logb(x)
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| returns the unbiased exponent of x, a signed integer in double precision,
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| except that logb(0) is -INF, logb(INF) is +INF, and logb(NAN) is that NAN.
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_logb:
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movw sp@(4),d0
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movw #0x7FF0,d1 | exponent bits
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andw d1,d0 | mask off all else
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cmpw d1,d0 | max exponent?
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bne Lfinite | no, is finite
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fmoved sp@(4),fp0 | yes, infinite or NaN
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fbun Ldone | NaN returns NaN
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fabsx fp0 | +-inf returns inf
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jra Ldone
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Lfinite:
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fmoved sp@(4),fp0 | get entire number
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fbne Lnonz | zero?
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flog2x fp0 | yes, log(0) a convenient source of -inf
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jra Ldone
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Lnonz:
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fgetexpx fp0 | get exponent
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jra Ldone
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| drem(x,y)
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| returns x REM y = x - [x/y]*y , where [x/y] is the integer nearest x/y;
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| in half way case, choose the even one.
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_drem:
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fmoved sp@(4),fp0
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fremd sp@(12),fp0
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fmoved fp0,sp@-
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movel sp@+,d0
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movel sp@+,d1
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rts
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| pow_p(x,y)
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| return x**y for x with sign=1 and finite y
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_pow_p:
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flognd sp@(4),fp0
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fmuld sp@(12),fp0
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fetoxx fp0
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fmoved fp0,sp@-
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movel sp@+,d0
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movel sp@+,d1
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rts
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| atan2__A(y,x)
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| compute atan2(y,x) where x,y are finite and non-zero
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| called by atan2() after weeding out all the special cases
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_atan2__A:
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moveq #0,d0 | sign of result
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fmoved sp@(4),fp0 | get y
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fboge Lypos | <0?
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moveq #1,d0 | yes, result is neg
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fnegx fp0 | make y pos
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Lypos:
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fmoved sp@(12),fp1 | get x
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fboge Lxpos | <0?
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fnegx fp1 | yes, make x pos
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fdivx fp1,fp0 | y/x
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fatanx fp0,fp1 | atan(y/x)
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fmovecr #0,fp0 | get pi
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fsubx fp1,fp0 | pi - atan(y/x)
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jra Lsetsign
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Lxpos:
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fdivx fp1,fp0 | y/x
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fatanx fp0 | atan(y/x)
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Lsetsign:
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tstl d0 | should be neg?
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jeq Lrpos | no, all done
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fnegx fp0 | yes, negate
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Lrpos:
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fmoved fp0,sp@-
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movel sp@+,d0
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movel sp@+,d1
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rts
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