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Routines |
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30278 | PUSH HL | |||||||||
30279 | LD HL,55583 | Blank out the 32-byte buffer at 55552 | ||||||||
30282 | XOR A | |||||||||
30283 | LD B,31 | |||||||||
30285 | LD (HL),A | |||||||||
30286 | DEC L | |||||||||
30287 | DJNZ 30285 | |||||||||
30289 | LD A,48 | 48 is the ASCII code for '0' (zero) | ||||||||
30291 | LD BC,55536 | BC=-10000 | ||||||||
30294 | EX DE,HL | HL=the number, DE=55552 | ||||||||
30295 | ADD HL,BC | Subtract 10000 | ||||||||
30296 | JR C,30325 | Jump if the number is > 10000 | ||||||||
30298 | SBC HL,BC | Add the 10000 back on | ||||||||
30300 | LD BC,64536 | BC=-1000 | ||||||||
30303 | ADD HL,BC | Subtract 1000 | ||||||||
30304 | JR C,30338 | Jump if the number is > 1000 | ||||||||
30306 | SBC HL,BC | Add the 1000 back on | ||||||||
30308 | LD BC,65436 | BC=-100 | ||||||||
30311 | ADD HL,BC | Subtract 100 | ||||||||
30312 | JR C,30351 | Jump if the number is > 100 | ||||||||
30314 | SBC HL,BC | Add the 100 back on | ||||||||
30316 | LD C,246 | BC=-10 | ||||||||
30318 | ADD HL,BC | Subtract 10 | ||||||||
30319 | JR C,30363 | Jump if the number is > 10 | ||||||||
30321 | SBC HL,BC | Add the 10 back on | ||||||||
30323 | JR 30371 | |||||||||
We get here if the number is >= 10000.
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30325 | INC A | Perform trial subtractions of 10000 and get the ASCII code for the 10000s digit in A | ||||||||
30326 | ADD HL,BC | |||||||||
30327 | JR C,30325 | |||||||||
30329 | SBC HL,BC | Undo the last trial subtraction | ||||||||
30331 | LD BC,64536 | BC=-1000 | ||||||||
30334 | LD (DE),A | Store the ASCII code for the 10000s digit | ||||||||
30335 | LD A,47 | |||||||||
30337 | INC E | Move along in the buffer | ||||||||
30338 | INC A | Perform trial subtractions of 1000 and get the ASCII code for the 1000s digit in A | ||||||||
30339 | ADD HL,BC | |||||||||
30340 | JR C,30338 | |||||||||
30342 | SBC HL,BC | Undo the last trial subtraction | ||||||||
30344 | LD BC,65436 | BC=-100 | ||||||||
30347 | LD (DE),A | Store the ASCII code for the 1000s digit | ||||||||
30348 | LD A,47 | |||||||||
30350 | INC E | Move along in the buffer | ||||||||
30351 | INC A | Perform trial subtractions of 100 and get the ASCII code for the 100s digit in A | ||||||||
30352 | ADD HL,BC | |||||||||
30353 | JR C,30351 | |||||||||
30355 | SBC HL,BC | Undo the last trial subtraction | ||||||||
30357 | LD (DE),A | Store the ASCII code for the 100s digit | ||||||||
30358 | INC E | Move along in the buffer | ||||||||
30359 | LD C,246 | BC=-10 | ||||||||
30361 | LD A,47 | |||||||||
30363 | INC A | Perform trial subtractions of 10 and get the ASCII code for the 10s digit in A | ||||||||
30364 | ADD HL,BC | |||||||||
30365 | JR C,30363 | |||||||||
30367 | SBC HL,BC | Undo the last trial subtraction | ||||||||
30369 | LD (DE),A | Store the ASCII code for the 10s digit | ||||||||
30370 | INC E | Move along in the buffer | ||||||||
30371 | LD A,L | Get the ASCII code for the units digit in A | ||||||||
30372 | ADD A,48 | |||||||||
30374 | LD (DE),A | Store the ASCII code for the units digit | ||||||||
30375 | XOR A | |||||||||
30376 | INC E | Move along in the buffer | ||||||||
30377 | LD (DE),A | Mark the end of the number string with a 0 byte | ||||||||
Now that the ASCII codes for the digits of the number have been calculated and stored at 55552, generate the corresponding graphic data.
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30378 | LD E,0 | DE=55552 (first character in the number string) | ||||||||
30380 | LD A,(DE) | Pick up a character from the number string | ||||||||
30381 | AND A | Have we reached the end of the string? | ||||||||
30382 | JR NZ,30386 | Jump if not | ||||||||
30384 | POP HL | |||||||||
30385 | RET | |||||||||
30386 | INC E | Move to the next character in the number string | ||||||||
30387 | EXX | |||||||||
30388 | LD L,A | L'=ASCII code for a digit of the number (48-57) | ||||||||
30389 | LD H,217 | Point HL' at the start of the font data for this digit | ||||||||
30391 | LD B,(HL) | Pick up the pixel width in B' | ||||||||
30392 | INC B | Add 1 for left padding | ||||||||
30393 | XOR A | An empty byte for left padding | ||||||||
30394 | INC H | Point HL' at the next bitmap byte | ||||||||
30395 | EXX | |||||||||
30396 | CALL 30258 | Slide the bitmap byte into the buffer | ||||||||
30399 | EXX | |||||||||
30400 | LD A,(HL) | Pick up the next bitmap byte | ||||||||
30401 | DJNZ 30394 | Jump back until all bitmap bytes are done | ||||||||
30403 | EXX | |||||||||
30404 | JR 30380 | Jump back to collect the next digit |
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