projects / pdp8.git / blame
| Commit | Line | Data |
|---|---|---|
| 7af5ad59 PH |
1 | / |
| 2 | / | |
| 3 | / SUBROUTINE DATAN(X) | |
| 4 | / | |
| 5 | / VERSION 5A 4-26-77 (MH) | |
| 6 | / | |
| 7 | /X,THE ARGUMENT, IS REDUCED TO | |
| 8 | /0<X<1/2 | |
| 9 | /BY THE IDENTITIES: | |
| 10 | /ATAN(-X)=-ATAN(X) | |
| 11 | /IF X>1.0 THEN ATAN(X)=PI/2 - ATAN(1/X) | |
| 12 | /IF .5<X<1.0 THEN ATAN(X)=ATAN(1/2)+ATAN(2*X-(1/(X+2))) | |
| 13 | /ATAN(X)=X FOR X<2^(-15) | |
| 14 | / | |
| 15 | / | |
| 16 | / | |
| 17 | SECT DATAN | |
| 18 | JA #DATAN | |
| 19 | DPCHK | |
| 20 | / | |
| 21 | TEXT +DATAN + | |
| 22 | DATNXR, SETX XRDATN | |
| 23 | SETB BPDATN | |
| 24 | BPDATN, F 0.0 | |
| 25 | XRDATN, F 0.0 | |
| 26 | DATFP1, F 1.0 | |
| 27 | F 0.0 | |
| 28 | DATLOW, -15 | |
| 29 | 2000 | |
| 30 | 0000 | |
| 31 | 0000 | |
| 32 | 0000 | |
| 33 | 0000 | |
| 34 | / | |
| 35 | ORG 10*3+BPDATN | |
| 36 | FNOP | |
| 37 | JA DATNXR | |
| 38 | 0 | |
| 39 | DATRTN, JA . | |
| 40 | / | |
| 41 | LAMBDA, 0004 | |
| 42 | 3057 | |
| 43 | 7537 | |
| 44 | 4017 | |
| 45 | 0276 | |
| 46 | 4536 | |
| 47 | DATB0, 0005 | |
| 48 | 3221 | |
| 49 | 3522 | |
| 50 | 3121 | |
| 51 | 3352 | |
| 52 | 5066 | |
| 53 | DATA1, 0007 | |
| 54 | 5372 | |
| 55 | 4104 | |
| 56 | 3437 | |
| 57 | 1766 | |
| 58 | 6167 | |
| 59 | DATB1, 0003 | |
| 60 | 3135 | |
| 61 | 1757 | |
| 62 | 0565 | |
| 63 | 4141 | |
| 64 | 4270 | |
| 65 | DATA2, 0001 | |
| 66 | 5473 | |
| 67 | 7524 | |
| 68 | 1112 | |
| 69 | 4701 | |
| 70 | 2723 | |
| 71 | DATB2, 0002 | |
| 72 | 2065 | |
| 73 | 4070 | |
| 74 | 1015 | |
| 75 | 2710 | |
| 76 | 3176 | |
| 77 | DATA3, 7775 | |
| 78 | 5374 | |
| 79 | 4326 | |
| 80 | 3317 | |
| 81 | 1675 | |
| 82 | 3124 | |
| 83 | DATB3, 0001 | |
| 84 | 2410 | |
| 85 | 5255 | |
| 86 | 0370 | |
| 87 | 2076 | |
| 88 | 6374 | |
| 89 | PIS2, 0001 | |
| 90 | 3110 | |
| 91 | 3755 | |
| 92 | 2421 | |
| 93 | 0264 | |
| 94 | 3013 | |
| 95 | ATN1S2, 7777 | |
| 96 | 3553 | |
| 97 | 0634 | |
| 98 | 0530 | |
| 99 | 3443 | |
| 100 | 6406 | |
| 101 | DATP5, 7777 | |
| 102 | 3777 | |
| 103 | 7777 | |
| 104 | 7777 | |
| 105 | 7777 | |
| 106 | 7776 | |
| 107 | X, F 0.0 | |
| 108 | F 0.0 | |
| 109 | C0, F 0.0 | |
| 110 | F 0.0 | |
| 111 | DT1, F 0.0 | |
| 112 | F 0.0 | |
| 113 | DATFP2, F 2.0 | |
| 114 | F 0.0 | |
| 115 | Z, F 0.0 | |
| 116 | F 0.0 | |
| 117 | / | |
| 118 | /PICK UP RETURN AND ARGUMENT | |
| 119 | BASE 0 | |
| 120 | #DATAN, STARTD | |
| 121 | FLDA 10*3 | |
| 122 | FSTA DATRTN | |
| 123 | FLDA 0 | |
| 124 | SETX XRDATN | |
| 125 | SETB BPDATN | |
| 126 | BASE BPDATN | |
| 127 | LDX 1,1 | |
| 128 | FSTA BPDATN | |
| 129 | FLDA% BPDATN,1 | |
| 130 | FSTA BPDATN | |
| 131 | STARTE | |
| 132 | FLDA% BPDATN /GET X | |
| 133 | LDX -1,0 /SIGN | |
| 134 | JGE .+5 | |
| 135 | LDX 0,0 /SAVE SIGN | |
| 136 | FNEG | |
| 137 | FSTA X /SAVE ARG | |
| 138 | / | |
| 139 | /CHECK ARGAINST LOWER LIMIT | |
| 140 | FLDA X | |
| 141 | FSUB DATLOW /TOO SMALL? | |
| 142 | JLE DATGO /YES ATAN(X)=X | |
| 143 | LDX -1,1 | |
| 144 | FCLA | |
| 145 | FSTA C0 | |
| 146 | / | |
| 147 | /REDUCE X TO RANGE 0<X<.5 | |
| 148 | DATA, FLDA X | |
| 149 | FSUB DATFP1 | |
| 150 | JLE DATB />1? | |
| 151 | FLDA DATFP1 /YES | |
| 152 | FDIV X /X=1/X | |
| 153 | LDX 0,1 /SET FLAG | |
| 154 | FSTA X | |
| 155 | DATB, FLDA X | |
| 156 | FSUB DATP5 />= .5 | |
| 157 | JLT DATC | |
| 158 | FLDA X /X=(2X-1)/(X+2) | |
| 159 | FADD DATFP2 | |
| 160 | FSTA DT1 /TEMP | |
| 161 | FLDA X | |
| 162 | FMUL DATFP2 | |
| 163 | FSUB DATFP1 | |
| 164 | FDIV DT1 | |
| 165 | FSTA X | |
| 166 | FLDA ATN1S2 /C0=ATAN(1/2) | |
| 167 | FSTA C0 | |
| 168 | /COMPUTE ATAN USING ALGORITHM | |
| 169 | DATC, FLDA X | |
| 170 | FMUL X | |
| 171 | FSTA Z /Z=X*X | |
| 172 | FLDA Z | |
| 173 | FADD DATB3 /Z+B3 | |
| 174 | FSTA DT1 | |
| 175 | FLDA DATA3 | |
| 176 | FDIV DT1 /A3/(Z+B3) | |
| 177 | FADD DATB2 | |
| 178 | FADD Z /ADD Z+B2 | |
| 179 | FSTA DT1 /TEMP | |
| 180 | FLDA DATA2 /A2/TEMP | |
| 181 | FDIV DT1 | |
| 182 | FADD DATB1 | |
| 183 | FADD Z /ADD Z +B1 | |
| 184 | FSTA DT1 /TEMP | |
| 185 | FLDA DATA1 /A1/TEMP | |
| 186 | FDIV DT1 | |
| 187 | FADD DATB0 /ADD Z+B0 | |
| 188 | FADD Z | |
| 189 | FSTA DT1 | |
| 190 | FLDA LAMBDA /LAMBDA*X | |
| 191 | FMUL X | |
| 192 | FDIV DT1 /DIV BY THE REST | |
| 193 | FADD C0 | |
| 194 | FSTA X | |
| 195 | JXN DATD,1 /WAS X>1 ORIGINALLY? | |
| 196 | FLDA PIS2 /Y ATAN(X)=PI/2-ATAN(X) | |
| 197 | FSUB X | |
| 198 | DATD, JXN DATRTN,0 /WAS X<0? | |
| 199 | FNEG /Y | |
| 200 | JA DATRTN | |
| 201 | DATGO, FLDA X | |
| 202 | JA DATD | |
| 203 | \f |