| ← C3D0 | Map | C443 → |
C41E: Load the next credits glyph into the marquee's load column
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Loads the next credit character from the credits message into the hidden rightmost marquee cell and advances the read pointer. At the message terminator it ends the scroll and reports the message exhausted.
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At the message terminator that frame's pixel shift is skipped.
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| credits_scroll_feed | C41E | LD HL,(credits_read_ptr) | Fetch the read pointer. | ||||
| C421 | LD A,(HL) | Read the next character; $00 marks the end of the message. | |||||
| C422 | OR A | ||||||
| C423 | JR NZ,credits_feed_have_char | ||||||
| C425 | POP HL | End of message: discard the return address back into the scroll step, so RET goes to the attract loop. A signals that the message is over. | |||||
| C426 | LD A,$FF | ||||||
| C428 | RET | ||||||
| credits_feed_have_char | C429 | INC HL | Advance the read pointer past this character. | ||||
| C42A | LD (credits_read_ptr),HL | ||||||
| C42D | LD H,$00 | Point HL at the code's glyph in the font, 8 bytes per glyph. | |||||
| C42F | LD L,A | ||||||
| C430 | ADD HL,HL | ||||||
| C431 | ADD HL,HL | ||||||
| C432 | ADD HL,HL | ||||||
| C433 | LD DE,FONT_BASE | ||||||
| C436 | ADD HL,DE | ||||||
| C437 | LD DE,SCREEN_BASE+$1077 | Destination: top pixel row of the rightmost marquee cell. | |||||
| C43A | LD B,$08 | Walk the glyph's pixel rows. | |||||
| credits_feed_copy_loop | C43C | LD A,(HL) | Copy each glyph row to the next pixel line of the cell (INC D steps down one line). | ||||
| C43D | LD (DE),A | ||||||
| C43E | INC D | ||||||
| C43F | INC HL | ||||||
| C440 | DJNZ credits_feed_copy_loop | ||||||
| C442 | RET | ||||||
| ← C3D0 | Map | C443 → |