| 1 | / |
| 2 | / |
| 3 | / A C O S |
| 4 | / - - - - |
| 5 | / |
| 6 | /SUBROUTINE ACOS(X) |
| 7 | / |
| 8 | / VERSION 5A 4-27-77 PT |
| 9 | / |
| 10 | SECT ACOS |
| 11 | JA #ACOS |
| 12 | TEXT +ACOS + |
| 13 | ACOSXR, SETX XRACOS |
| 14 | SETB BPACOS |
| 15 | BPACOS, FNOP |
| 16 | 0 |
| 17 | 0 |
| 18 | XRACOS, F 0.0 |
| 19 | ACOS8, F 0.0 |
| 20 | ACOS7, F 0.0 |
| 21 | FPI2AC, 1 /PI OVER 2 |
| 22 | 3110 |
| 23 | 3755 |
| 24 | F1ACOS, F 1. |
| 25 | FPIACS, 2 /PI |
| 26 | 3110 |
| 27 | 3755 |
| 28 | ORG 10*3+BPACOS |
| 29 | FNOP |
| 30 | JA ACOSXR |
| 31 | 0 |
| 32 | ACSRTN, JA . |
| 33 | BASE 0 |
| 34 | #ACOS, STARTD |
| 35 | FLDA 10*3 |
| 36 | FSTA ACSRTN |
| 37 | FLDA 0 |
| 38 | SETX XRACOS |
| 39 | SETB BPACOS |
| 40 | BASE BPACOS |
| 41 | LDX 1,1 |
| 42 | FSTA BPACOS |
| 43 | FLDA% BPACOS,1 /ADDR OF X |
| 44 | FSTA BPACOS |
| 45 | STARTF |
| 46 | FLDA% BPACOS /GET X |
| 47 | FSTA ACOS8 /SAVE IT |
| 48 | JEQ ACOSEQ /IF 0 RTN PI OVER 2 |
| 49 | LDX -1,0 /JUMP TIME |
| 50 | JGE .+5 |
| 51 | LDX 0,0 |
| 52 | FNEG |
| 53 | FSUB F1ACOS /1-!X! |
| 54 | JLE ACOSOK /IS IT <1.? |
| 55 | EXTERN #ARGER |
| 56 | TRAP4 #ARGER |
| 57 | JA ACSRTN /AND RETURN |
| 58 | ACOSOK, FLDA ACOS8 /X |
| 59 | FMUL ACOS8 /X^2 |
| 60 | FNEG /-X^2 |
| 61 | FADD F1ACOS /1-X^2 |
| 62 | FSTA ACOS7 |
| 63 | EXTERN SQRT |
| 64 | JSR SQRT /CALL SQRT |
| 65 | JA .+4 /SQRT (1-X^2) |
| 66 | JA ACOS7 |
| 67 | FDIV ACOS8 /SQRT (1-X^2)/X |
| 68 | FSTA ACOS7 |
| 69 | EXTERN ATAN |
| 70 | JSR ATAN /CALL ATAN |
| 71 | JA .+4 /ATAN (SQRT(1-X^2)/X) |
| 72 | JA ACOS7 |
| 73 | JXN ACSRTN,0 /NO SIGN CHG NECESSARY |
| 74 | FADD FPIACS /ADD PI IF MINUE |
| 75 | JA ACSRTN |
| 76 | ACOSEQ, FLDA FPI2AC /RTN PI OVER 2 IF 0 |
| 77 | JA ACSRTN |
| 78 | \f |