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Annotation of 42BSD/usr.lib/libnm/log.s, revision 1.1.1.1

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

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