Linear congruential generator: Difference between revisions
Added solution for EDSAC.
m (Phix/mpfr) |
(Added solution for EDSAC.) |
||
Line 1,016:
18467
6334</pre>
=={{header|EDSAC order code}}==
The first version of this solution had trouble with the "sandwich digit". As pointed out by Wilkes, Wheeler & Gill (1951 edition, page 26), a 35-bit constant cannot be loaded via pseudo-orders if the middle bit (sandwich digit) is 1. One workaround, adopted in the EDSAC solution to the Babbage Problem, is to use the negative of the constant instead. The alternative, which WWG evidently preferred and which is used in the LCG solution posted here, is to load 35-bit constants via the library subroutine R9.
The task doesn't specify what random seed is to be used. This program uses 1, with results identical to those from the Elixir program.
<lang edsac>
[Linear congruential generators for pseudo-random numbers.
EDSAC program, Initial Orders 2.]
[Library subroutine R9, to read integer constants at load time.
See Wilkes, Wheeler & Gill, 1951 edition, pages 98 & 148.]
..PK
T 56 K [must be loaded at 56]
GKT20FVDL8FA40DUDTFI40FA40FS39FG@S2FG23FA5@T5@E4@
[Modification of library subroutine P7.
Prints non-negative integer, up to 10 digits, right-justified.
55 locations, load at even address.
Set up to be called with 'G N', so that caller needn't know its address.
See Wilkes, Wheeler & Gill, 1951 edition, page 18.]
T 46 K [location corresponding to N parameter]
P 72 F [load subroutine at 72]
E 25 K TN
GKA3FT42@A47@T31@ADE10@T31@A48@T31@SDTDH44#@NDYFLDT4DS43@TF
H17@S17@A43@G23@UFS43@T1FV4DAFG50@SFLDUFXFOFFFSFL4FT4DA49@T31@
A1FA43@G20@XFP1024FP610D@524D!FO46@O26@XFO46@SFL8FT4DE39@
[BSD linear congruential generator.
Call with 'G B' to initialize, passing seed in 0D.
Call with 'G 1 B' to get next value, returned in 0D.]
T 53 K [location corresponding to B parameter]
P 140 F [load subroutine at 140]
E 25 K TB GK
[0] G 10 @ [jump to initialize]
[1] G 15 @ [jump to get next value]
[2] PF PF [mask, 2^31 - 1]
[4] PF PF [multiplier]
[6] PF PF [added constant]
[Call R9 to set the 3 preceding constants at load time.]
E69KT2#@
2147483647F1103515245F12345#
T8Z
[8] PF PF [current state]
[Initialize; caller places seed in 0D]
[10] A 3 F [make jump back to caller]
T 14 @ [plant in code]
A D [load seed passed by caller]
T 8#@ [store as initial state]
[14] Z F [overwritten by jump back to caller]
[Get next value from BSD; return it in 0D]
[15] A 3 F [make jump back to caller]
T 28 @ [plant in code, acc := 0]
H 4#@ [mult reg := multiplier]
V 8#@ [acc := state * multiplier]
LF LF L64F [shift 34 left, done as 13 + 13 + 8]
A 6#@ [add the constant]
T D [temp store in 0D]
H 2#@ [mult reg := mask]
C D [acc := result modulo 2^31]
U 8#@ [update state]
T D [also to 0D for caller]
[28] Z F [overwritten by jump back to caller]
[Microsoft linear congruential generator.
Call with 'G M' to initialize, passing seed in 0D.
Call with 'G 1 M' to get next value, returned in 0D.
Very similar to code for BSD, so given in condensed form.]
T47KP180FE25KTMGKG10@G15@PFPFPFPFPFPFE69KT2#@
2147483647F214013F2531011# [the 3 constants]
T8ZPFPFA3FT14@ADT8#@ZFA3FT30@H4#@V8#@LFLFL64FA6#@TDH2#@CDU8#@
[Unlike BSD, MS returns the state divided by 2^16]
RF RD [shift 16 right, done as 15 + 1]
T D [to 0D for caller]
[30] Z F [overwritten by jump back to caller]
[Main routine]
T 220 K [load at 220]
G K [set theta parameter as usual]
[0] PF PF [35-bit seed]
[Use library subroutine R9 to set seed]
E69K T#@
1# [non-negative seed followed by '#']
T2Z
[2] P F [negative counter for loop]
[3] P 10 F [to print first 10 values]
[Characters for printing]
[4] B F
[5] D F
[6] E F
[7] M F
[8] S F
[9] C F [colon when in figures mode]
[10] K 2048 F [set letters on teleprinter]
[11] # F [set figures on teleprinter]
[12] @ F [carriage return]
[13] & F [line feed]
[14] K 4096 F [null]
[Enter with acc = 0]
[Print 'SEED:' and then the seed]
[15] O10@ O8@ O6@ O6@ O5@ O11@ O9@
A #@ [load seed]
T D [store in 0D for printing]
[24] A 24 @ [pass return address]
G N [call print subroutine]
O12@ O13@ [print new line]
[Initialize the BSD generator]
A #@ [load seed]
T D [pass seed in 0D]
[30] A 30 @ [pass return address]
G B [call BSD initializer]
O10@ O4@ O8@ O5@ O11@ O9@ O12@ O13@ [print 'BSD:']
S 3 @ [load negative of count]
[Loop printing values from BSD generator]
[41] T 2 @ [update negative counter]
[42] A 42 @ [pass return address]
G 1 B [call BSD to get next value in 0D]
[44] A 44 @ [pass return address]
G N [call print subroutine]
O12@ O13@ [print new line]
A 2 @ [load negative counter]
A 2 F [increment]
G 41 @ [loop until counter = 0]
[Microsoft LCG, very similar to BSD, so given in condensed form]
A#@TDA53@GMO10@O7@O8@O11@O9@O12@O13@S3@T2@A64@G1MA66@GNO12@O13@A2@A2FG63@
O 14 @ [print null to flush teleprinter buffer]
Z F [stop]
E 15 Z [define entry point]
P F [acc = 0 on entry]
</lang>
{{out}}
<pre>
SEED: 1
BSD:
1103527590
377401575
662824084
1147902781
2035015474
368800899
1508029952
486256185
1062517886
267834847
MS:
41
18467
6334
26500
19169
15724
11478
29358
26962
24464
</pre>
=={{header|Elixir}}==
| |||