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generating_20pseudo-random_20numbers

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generating_20pseudo-random_20numbers [2018/03/31 13:19]
127.0.0.1 external edit
generating_20pseudo-random_20numbers [2018/04/13 10:43] (current)
richardrussell
Line 38: Line 38:
         mov  [seed],eax         mov  [seed],eax
         ret         ret
-You can test the code from BASIC as follows:\\ \\ +You can test the code from BASIC as follows: 
 + 
 +<code bb4w> ​
         CALL Randomise         CALL Randomise
         FOR I% = 1 TO 20         FOR I% = 1 TO 20
           PRINT ~ USR(Rnd)           PRINT ~ USR(Rnd)
         NEXT         NEXT
 +</​code>​
 +
 ==== RND(N) ==== ==== RND(N) ====
 \\  The subroutine below provides a direct equivalent to RND(N), where N is a positive integer greater than 1. Each time it is called it returns a pseudo-random integer in the range 1 to N, in the eax register:\\ \\  \\  The subroutine below provides a direct equivalent to RND(N), where N is a positive integer greater than 1. Each time it is called it returns a pseudo-random integer in the range 1 to N, in the eax register:\\ \\ 
Line 58: Line 62:
         inc  eax         inc  eax
         ret         ret
-The parameter N is passed to the subroutine in the ebx register. If you prefer to return a number in the range 0 to N-1 just delete the **inc eax** instruction.\\ \\  You can test the code from BASIC as follows:\\ \\ +The parameter N is passed to the subroutine in the ebx register. If you prefer to return a number in the range 0 to N-1 just delete the **inc eax** instruction.\\ \\  You can test the code from BASIC as follows: 
 + 
 +<code bb4w> ​
         CALL Randomise         CALL Randomise
         FOR I% = 1 TO 20         FOR I% = 1 TO 20
Line 64: Line 70:
           PRINT USR(RndRange)           PRINT USR(RndRange)
         NEXT         NEXT
 +</​code>​
 +
 ==== RND(1) ==== ==== RND(1) ====
 \\  The subroutine below provides a direct equivalent to RND(1). Each time it is called it returns a pseudo-random 64-bit floating-point value (double) in the range 0.0 to 1.0:\\ \\  \\  The subroutine below provides a direct equivalent to RND(1). Each time it is called it returns a pseudo-random 64-bit floating-point value (double) in the range 0.0 to 1.0:\\ \\ 
Line 82: Line 90:
           mov  [ebx+4],ecx           mov  [ebx+4],ecx
           ret           ret
-The value is returned in memory at the address passed in the ebx register.\\ \\  You can test the code from BASIC as follows:\\ \\ +The value is returned in memory at the address passed in the ebx register.\\ \\  You can test the code from BASIC as follows: 
 + 
 +<code bb4w> ​
         CALL Randomise         CALL Randomise
         FOR I% = 1 TO 20         FOR I% = 1 TO 20
Line 89: Line 99:
           PRINT R#           PRINT R#
         NEXT         NEXT
 +</​code>​
generating_20pseudo-random_20numbers.txt · Last modified: 2018/04/13 10:43 by richardrussell