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Routines |
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| $213B | LDA $9D | Pick up the width (in character cells) of the target message box from $9D and multiply by 8 to get the width in pixels. | ||||||||
| $213D | ASL A | |||||||||
| $213E | ASL A | |||||||||
| $213F | ASL A | |||||||||
| $2140 | SEC | Subtract the number of pixel columns that have been inserted into the text graphic buffer. | ||||||||
| $2141 | SBC $A2 | |||||||||
| $2143 | BMI $2155 | Return if the buffer is already full (no centring required). | ||||||||
| $2145 | CMP #$02 | Are there fewer than two free pixel columns remaining? | ||||||||
| $2147 | BCC $2155 | Return if so (no centring required). | ||||||||
| $2149 | LSR A | Divide A by 2 and store the result at $57. This is the number of pixel columns by which the message will be shifted in order to centre it. | ||||||||
| $214A | STA $57 | |||||||||
| $214C | LDA #$00 | Insert a blank pixel column into the text graphic buffer at $4500. | ||||||||
| $214E | JSR $20F5 | |||||||||
| $2151 | DEC $57 | Is the message centred yet? | ||||||||
| $2153 | BNE $214C | Branch back if not. | ||||||||
| $2155 | RTS | |||||||||
| Prev: $212A | Up: Map | Next: $2156 |