| The Android Open Source Project | b07e1d9 | 2009-03-03 19:29:30 -0800 | [diff] [blame] | 1 | 21 Oct 2002 |
| 2 | bug fix in e_pow.c from "David G Hough at validlab.com" <validlab@validlab.com>. |
| 3 | credit for bug report goes to andrew_johnson@uk.ibm.com |
| 4 | test example: |
| 5 | ----------------------------- |
| 6 | static int fail=0; |
| 7 | |
| 8 | trypow(x,y,z) |
| 9 | double x,y,z; |
| 10 | { |
| 11 | extern double ieee_pow(); |
| 12 | double p ; |
| 13 | |
| 14 | p = ieee_pow(x,y); |
| 15 | if (p != z) { |
| 16 | printf(" pow failure x %e y %e computed %e correct %e \n",x,y,p,z); |
| 17 | fail++; |
| 18 | return; |
| 19 | } |
| 20 | if (1/p != 1/z) { |
| 21 | printf(" pow failure x %e y %e computed %e correct %e \n",x,y,p,z); |
| 22 | fail++; |
| 23 | return; |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | main() |
| 28 | { |
| 29 | |
| 30 | trypow( 1.0000000001, 1.0000000001E10, 2.7182820535066154); |
| 31 | trypow(-1.0000000001, 1.0000000001E10, -2.7182820535066154); |
| 32 | trypow(-0.001, 1.0000000001E10, -0.0); |
| 33 | trypow(-1000.0, 1.0000000001E10, -1.0/0.0); |
| 34 | |
| 35 | if (fail == 0) { |
| 36 | printf(" fdlibm e_pow.c seems to be current \n"); |
| 37 | exit(0); |
| 38 | } |
| 39 | else { |
| 40 | printf(" fdlibm e_pow.c seems to be out of date \n"); |
| 41 | exit(1); |
| 42 | } |
| 43 | |
| 44 | } |
| 45 | ----------------------------- |
| 46 | |
| 47 | |
| 48 | |
| 49 | What's new in FDLIBM 5.3? |
| 50 | |
| 51 | CONFIGURE |
| 52 | To build FDLIBM, edit the supplied Makefile or create |
| 53 | a local Makefile by running "sh configure" |
| 54 | using the supplied configure script contributed by Nelson Beebe |
| 55 | |
| 56 | BUGS FIXED |
| 57 | |
| 58 | 1. e_pow.c incorrect results when |
| 59 | x is very close to -1.0 and y is very large, e.g. |
| 60 | ieee_pow(-1.0000000000000002e+00,4.5035996273704970e+15) = 0 |
| 61 | ieee_pow(-9.9999999999999978e-01,4.5035996273704970e+15) = 0 |
| 62 | Correct results are close to -e and -1/e. |
| 63 | |
| 64 | 2. k_tan.c error was > 1 ulp target for FDLIBM |
| 65 | 5.2: Worst error at least 1.45 ulp at |
| 66 | ieee_tan(1.7765241907548024E+269) = 1.7733884462610958E+16 |
| 67 | 5.3: Worst error 0.96 ulp |
| 68 | |
| 69 | NOT FIXED YET |
| 70 | |
| 71 | 3. Compiler failure on non-standard code |
| 72 | Statements like |
| 73 | *(1+(int*)&t1) = 0; |
| 74 | are not standard C and cause some optimizing compilers (e.g. GCC) |
| 75 | to generate bad code under optimization. These cases |
| 76 | are to be addressed in the next release. |
| 77 | |