Routines
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26070: Generate Random Number
Used by the routines at GameLoop and ActionKill.
Returns a number from 0 up to, but not including, A.
The frame counter chooses how far to walk around that range.
Input
A Exclusive upper bound
Output
A The generated number
Mix the frame counter into a number below the limit in A.
GenerateRandomNumber 26070 PUSH BC Stash BC on the stack.
26071 LD C,A Store the exclusive upper bound in C.
26072 LD A,(23672) Load *FRAMES into B as the loop count.
26075 LD B,A
26076 LD A,C Restore the exclusive upper bound into A.
GenerateRandomNumber_Loop 26077 DEC A Decrease the walking value by one.
26078 JR NZ,GenerateRandomNumber_Next Jump to GenerateRandomNumber_Next if it has not wrapped past zero.
26080 LD A,C Wrap back to the exclusive upper bound.
GenerateRandomNumber_Next 26081 DJNZ GenerateRandomNumber_Loop Decrease the frame-count loop by one and loop back to GenerateRandomNumber_Loop until the count is zero.
26083 DEC A Decrease the result by one so the range starts at 0.
26084 POP BC Restore BC from the stack.
26085 RET Return.
View the equivalent code in;
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