4.3BSD - /usr/src/usr.lib/liboldnm/log.s

   1: #
   2: # Copyright (c) 1980 Regents of the University of California.
   3: # All rights reserved.  The Berkeley software License Agreement
   4: # specifies the terms and conditions for redistribution.
   5: #
   6: #	@(#)log.s	5.1 (Berkeley) 5/8/85
   7: #
   8: #
   9: # double log(arg) ; natural logarithm
  10: # double log10(arg); base 10 log
  11: # double arg
  12: # if(arg<=0){ errno=EDOM; return(-1.7e+38); }
  13: # nat. log computed from Hart&Cheney LOGE 2706 D=22.1
  14: # J F Jarvis August 3, 1978
  15: .set    EDOM,33
  16: .globl  _log
  17: .globl  _log10
  18: .globl  _errno
  19: .text
  20: .align  1
  21: _log10:
  22:         .word   0x0
  23:         bispsw  $0xe0
  24:         movd    4(ap),-(sp)
  25:         calls   $2,_log
  26:         muld2   log10e,r0
  27:         ret
  28: .align  1
  29: _log:
  30:         .word   0x07c0
  31:         bispsw  $0xe0
  32:         movd    4(ap),r0
  33:         jgtr    range
  34:         movl    $EDOM,_errno
  35:         movd    $0d-1.7e+38,r0  # machine dept max neg
  36:         ret
  37: range:
  38:         extzv   $7,$8,r0,r10    # r10 = exp(arg)+128
  39:         insv    $128,$7,$8,r0   # r0,r1: 0.5<=frac(arg)<1.0
  40:         cmpd    r0,sqrt2d2
  41:         jgeq    comp
  42:         insv    $129,$7,$8,r0   # frac *= 2
  43:         decl    r10                             # exp -= 1
  44: comp:
  45:         subl2   $128,r10        # signed exp for scaled arg
  46:         subd3   $0d1.0e+0,r0,r6 # Hart&cheney LOGE 2706
  47:         addd2   $0d1.0e+0,r0
  48:         divd2   r0,r6   # r6,r7= (frac-1)/(frac+1)
  49:         muld3   r6,r6,r8
  50:         polyd   r8,$3,pcoef
  51:         muld2   r0,r6
  52:         polyd   r8,$4,qcoef
  53:         divd3   r0,r6,r0
  54:         cvtld   r10,r2
  55:         muld2   log2,r2 # r2,r3= loge(2**exp)
  56:         addd2   r2,r0
  57:         ret
  58: .data
  59: .align  2
  60: pcoef:
  61:         .double 0d-0.24550691103445385056e+2
  62:         .double 0d0.23616053565907671809e+3
  63:         .double 0d-0.54904361859132995001e+3
  64:         .double 0d0.35621151669903912407e+3
  65: qcoef:
  66:         .double 0d0.10e+1
  67:         .double 0d-0.35526251110400238735e+2
  68:         .double 0d0.19375591463035879517e+3
  69:         .double 0d-0.33389039541217149928e+3
  70:         .double 0d0.17810575834951956204e+3
  71: log10e:
  72:         .double 0d0.43429448190325182765e+0
  73: sqrt2d2:
  74:         .double 0d0.70710678118654752440e+0
  75: log2:
  76:         .double 0d0.69314718055994530941e+0

Defined functions

Defined variables