Routines
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46473: Print Character
Used by the routines at HallOfFame, PrintStringColour, Score_1UP, EnterInitials and DisplayPlayerLives.
Prints a character from the font pointed to by the system variable CHARS onto the screen, at an address on the screen, and moves to the next column.
Before
character-before
After PrintScreen
character-after
Input
A ASCII value to print
HL Screen address
Output
HL Screen address of the next character
PrintScreen 46473 PUSH BC Stash BC, DE and HL on the stack.
46474 PUSH DE
46475 PUSH HL
46476 LD L,A Use the character code as the offset into the font.
46477 LD H,0
46479 ADD HL,HL Multiply the offset by eight (the number of bytes in a character).
46480 ADD HL,HL
46481 ADD HL,HL
46482 LD DE,(23606) Fetch the address of the font from CHARS.
46486 ADD HL,DE DE=HL + 15360. For examples of usage;
Letter ASCII Value * 8 (offset) CHARS + offset
"U" 85 680 16040
"L" 76 608 15968
"T" 84 672 16032
"I" 73 584 15944
"M" 77 616 15976
"A" 65 520 15880
"T" 84 672 16032
"E" 69 552 15912
46487 EX DE,HL
Print the character to the screen.
46488 POP HL Restore the screen address.
This entry point is used by the routine at DisplayPlayerLives.
PrintScreen_Write 46489 LD B,8 Set the number of pixel lines in B to 8.
PrintScreen_Loop 46491 LD A,(DE) Draw a pixel line of the character.
46492 LD (HL),A
46493 INC DE Move onto the next pixel line of the character.
46494 INC H Move onto the next pixel line of the screen.
46495 DJNZ PrintScreen_Loop Decrease the pixel line counter by one and loop back to PrintScreen_Loop until all eight pixel lines have been drawn.
46497 POP DE Restore the registers from the stack.
46498 POP BC
Reset HL and move to the next column, ready to print the next character.
46499 LD A,H H=H - 8 (reset the display line).
46500 SUB 8
46502 LD H,A
46503 INC L Move onto the next column.
46504 RET Return.
View the equivalent code in;
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