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Routines |
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The routine at CL_ALL continues here.
This subroutine is entered with the BC register pair holding the line and column numbers of a character area, or the C register holding the column number within the printer buffer. The appropriate address of the first character bit is then found. The subroutine returns via PO_STORE so as to store all the values in the required system variables.
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| CL_SET | 0DD9 | LD HL,$5B00 | The start of the printer buffer. | |||||||
| 0DDC | BIT 1,(IY+$01) | Jump forward if handling the printer buffer (bit 1 of FLAGS set). | ||||||||
| 0DE0 | JR NZ,CL_SET_2 | |||||||||
| 0DE2 | LD A,B | Transfer the line number. | ||||||||
| 0DE3 | BIT 0,(IY+$02) | Jump forward if handling the main part of the display (bit 0 of TV-FLAG reset). | ||||||||
| 0DE7 | JR Z,CL_SET_1 | |||||||||
| 0DE9 | ADD A,(IY+$31) | The top line of the lower part of the display is called 'line +18' and this has to be converted (see DF-SZ). | ||||||||
| 0DEC | SUB $18 | |||||||||
| CL_SET_1 | 0DEE | PUSH BC | The line and column numbers are saved. | |||||||
| 0DEF | LD B,A | The line number is moved. | ||||||||
| 0DF0 | CALL CL_ADDR | The address for the start of the line is formed in HL. | ||||||||
| 0DF3 | POP BC | The line and column numbers are fetched back. | ||||||||
| CL_SET_2 | 0DF4 | LD A,$21 | The column number is now reversed and transferred to the DE register pair. | |||||||
| 0DF6 | SUB C | |||||||||
| 0DF7 | LD E,A | |||||||||
| 0DF8 | LD D,$00 | |||||||||
| 0DFA | ADD HL,DE | The required address is now formed, and the address and the line and column numbers are stored by jumping to PO_STORE. | ||||||||
| 0DFB | JP PO_STORE | |||||||||
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