Routines |
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Used by the routine at compare.
The address of this routine is found in the table of addresses. It is called via the calculator literal +01 by the routines at BEEP, OPEN, FOR, NEXT_LOOP, CIRCLE, DRAW, CD_PRMS1, INT_TO_FP, PRINT_FP, series, n_mod_m, int, ln, get_argt, tan, atn and to_power.
This binary operation 'exchanges' the first number with the second number, i.e. the topmost two numbers on the calculator stack are exchanged.
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exchange | 343C | LD B,$05 | There are five bytes involved. | |||||||||||
SWAP_BYTE | 343E | LD A,(DE) | Each byte of the second number. | |||||||||||
343F | LD C,(HL) | Each byte of the first number. | ||||||||||||
3440 | EX DE,HL | Switch source and destination. | ||||||||||||
3441 | LD (DE),A | Now to the first number. | ||||||||||||
3442 | LD (HL),C | Now to the second number. | ||||||||||||
3443 | INC HL | Move to consider the next pair of bytes. | ||||||||||||
3444 | INC DE | |||||||||||||
3445 | DJNZ SWAP_BYTE | Exchange the five bytes. | ||||||||||||
3447 | EX DE,HL | Get the pointers correct as 5 is an odd number. | ||||||||||||
3448 | RET | Finished. |
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