projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 8daa8d7c DF |
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) %G% | |
| 7 | # | |
| 8 | # | |
| 65ebf766 DF |
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 |