Routines
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27798: Print Character
Used by the routines at PrintStringColour, DrawPlayArea and Score_Player.
Input
A ASCII value to print
HL Screen address
PrintScreen 27798 PUSH BC Stash BC, DE and HL on the stack.
27799 PUSH DE
27800 PUSH HL
27801 LD L,A Create an offset in HL.
27802 LD H,0
27804 ADD HL,HL Calculate offset for ASCII character (HL=HL * 8).
27805 ADD HL,HL
27806 ADD HL,HL
27807 LD DE,(23606) DE=CHARS.
27811 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
27812 EX DE,HL
Print the character to the screen.
27813 POP HL Restore HL, containing the screen buffer location, from the stack.
27814 LD B,8 B=8 (8 rows of pixels).
PrintScreen_Loop 27816 LD A,(DE) Copy a byte from the font data to the screen buffer.
27817 LD (HL),A
27818 INC DE Increment the font data by one.
27819 INC H Move onto the next pixel line.
27820 DJNZ PrintScreen_Loop Decrease counter by one and loop back to PrintScreen_Loop until counter is zero.
27822 POP DE Restore DE and BC from the stack.
27823 POP BC
Reset HL and move to the next column, ready to print the next character.
27824 LD A,H H=H - 8 (reset the display line).
27825 SUB 8
27827 LD H,A
27828 INC L Increment screen column by one.
27829 RET Return.
View the equivalent code in;
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