projects / pdp8.git / blame
| Commit | Line | Data |
|---|---|---|
| 7af5ad59 PH |
1 | /SQUARE ROOT SUBROUTINE OS8 FORTRAN II LIBRARY LIBRARY |
| 2 | / | |
| 3 | / | |
| 4 | / | |
| 5 | / | |
| 6 | / | |
| 7 | / | |
| 8 | / | |
| 9 | / | |
| 10 | / | |
| 11 | /COPYRIGHT (C) 1974,1977 BY DIGITAL EQUIPMENT CORPORATION | |
| 12 | / | |
| 13 | / | |
| 14 | / | |
| 15 | / | |
| 16 | / | |
| 17 | / | |
| 18 | / | |
| 19 | / | |
| 20 | / | |
| 21 | / | |
| 22 | /THE INFORMATION IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE | |
| 23 | /AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT | |
| 24 | /CORPORATION. DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY | |
| 25 | /FOR ANY ERRORS THAT MAY APPEAR IN THIS MANUAL. | |
| 26 | / | |
| 27 | /THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED TO THE PURCHASER | |
| 28 | /UNDER A LICENSE FOR USE ON A SINGLE COMPUTER SYSTEM AND CAN BE COPIED | |
| 29 | /(WITH INCLUSION OF DIGITAL'S COPYRIGHT NOTICE) ONLY FOR USE IN SUCH | |
| 30 | /SYSTEM, EXCEPT AS MAY OTHERWISE BE PROVIDED IN WRITING BY DIGITAL. | |
| 31 | / | |
| 32 | /DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY FOR THE USE | |
| 33 | /OR RELIABILITY OF ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY | |
| 34 | /DIGITAL. | |
| 35 | / | |
| 36 | / | |
| 37 | / | |
| 38 | / | |
| 39 | / | |
| 40 | / | |
| 41 | / | |
| 42 | / | |
| 43 | / | |
| 44 | / | |
| 45 | \f/ VERSION 4A | |
| 46 | / VERSION NUMBER IS AVAILABLE AT ENTRY POINTS | |
| 47 | ENTRY SQRT | |
| 48 | / | |
| 49 | / SQUARE ROOT ROUTINE | |
| 50 | / IF X0 IS AN APPROXIMATION FOR Y**(1/2) | |
| 51 | / THEN (X0+(Y/X0))/2 IS A BETTER APPROXIMATION | |
| 52 | / | |
| 53 | X0, BLOCK 3 | |
| 54 | Y, BLOCK 3 | |
| 55 | CNT, BLOCK 1 | |
| 56 | / | |
| 57 | / | |
| 58 | CPAGE 4 | |
| 59 | SQER, 6321 /"SQRT" ERROR FROM LOC XXXXX | |
| 60 | 2224 | |
| 61 | SQRT, BLOCK 1 | |
| 62 | 4 /ENTRY POINT | |
| 63 | TAD I SQRT | |
| 64 | DCA IN | |
| 65 | INC SQRT# | |
| 66 | TAD I SQRT | |
| 67 | DCA IN# | |
| 68 | ISZ SQRT# | |
| 69 | CALL 1,FAD | |
| 70 | IN, ARG 0 | |
| 71 | CALL 1,STO /Y=ARGUMENT | |
| 72 | ARG Y | |
| 73 | CALL 1,FAD | |
| 74 | ARG Y | |
| 75 | TAD ACH /IF Y NEGATIVE THEN ERROR | |
| 76 | SMA | |
| 77 | JMP POS | |
| 78 | CALL 1,ERROR | |
| 79 | ARG SQER | |
| 80 | CLA CLL CMA RAR | |
| 81 | AND ACH | |
| 82 | POS, SZA /IF Y=0 THEN ROOT=0 | |
| 83 | JMP NONZ | |
| 84 | RETRN SQRT | |
| 85 | NONZ, RAR CLL /FORM INITIAL APPROXIMATION | |
| 86 | TAD (1004 | |
| 87 | DCA ACH | |
| 88 | TAD ACM | |
| 89 | RAR | |
| 90 | DCA ACM | |
| 91 | TAD ACL | |
| 92 | RAR | |
| 93 | DCA ACL | |
| 94 | TAD ACH | |
| 95 | AND (4 | |
| 96 | SNA CLA | |
| 97 | TAD (2 | |
| 98 | TAD ACH | |
| 99 | DCA ACH | |
| 100 | TAD (-3 /DO 3 ITERATIONS | |
| 101 | DCA CNT | |
| 102 | INIT, CALL 1,STO | |
| 103 | ARG X0 | |
| 104 | CALL 1,FAD | |
| 105 | ARG Y | |
| 106 | CALL 1,FDV /Y/X0 | |
| 107 | ARG X0 | |
| 108 | CALL 1,FAD /(Y/X0)+X0 | |
| 109 | ARG X0 | |
| 110 | TAD ACH /((Y/X0)+X0)/2 | |
| 111 | TAD (7770 | |
| 112 | DCA ACH | |
| 113 | ISZ CNT | |
| 114 | JMP INIT | |
| 115 | RETRN SQRT | |
| 116 | END | |
| 117 | \f |