Routines
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7468: Print Character
Used by the routines at 5FE1, 7378, Score_1UP and PrintString.
Input
A ASCII value to print
HL Screen address
PrintScreen 7468 PUSH BC Stash BC, DE and HL on the stack.
7469 PUSH DE
746A PUSH HL
746B LD L,A Create an offset in HL.
746C LD H,$00
746E ADD HL,HL HL=HL * 8.
746F ADD HL,HL
7470 ADD HL,HL
7471 LD DE,($5C36) DE=CHARS.
7475 ADD HL,DE DE=HL + 3C00. For examples of usage;
Letter ASCII Value * 8 (offset) CHARS + offset
"U" 55 02A8 3EA8
"L" 4C 0260 3E60
"T" 54 02A0 3EA0
"I" 49 0248 3E48
"M" 4D 0268 3E68
"A" 41 0208 3E08
"T" 54 02A0 3EA0
"E" 45 0228 3E28
7476 EX DE,HL
Print the character to the screen.
7477 POP HL Restore HL, containing the screen buffer location, from the stack.
This entry point is used by the routine at 7378.
PrintScreen_0 7478 LD B,$08 B=08 (08 rows of pixels).
PrintScreen_Loop 747A LD A,(DE) Copy a byte from the font data to the screen buffer.
747B LD (HL),A
747C INC DE Increment the font data by one.
747D INC H Move onto the next pixel line.
747E DJNZ PrintScreen_Loop Decrease counter by one and loop back to PrintScreen_Loop until counter is zero.
7480 POP DE Restore DE and BC from the stack.
7481 POP BC
Reset HL and move to the next column, ready to print the next character.
7482 LD A,H H=H - 08 (reset the display line).
7483 SUB $08
7485 LD H,A
7486 INC L Increment screen column by one.
7487 RET Return.
View the equivalent code in;
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