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Routines |
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Used by the routine at Draw_Special_Room_Parts.
Draws the picture of the left wall of a special room, at x position 00 and y position 30. The picture is three bytes wide and 70 lines high (see Room_Graphics_Left_Wall).
The attributes of the picture are bright cyan (4D). The shared code from Draw_Wall_Picture onwards also draws the right wall (see Draw_Right_Wall_Picture).
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| Draw_Left_Wall_Picture | 9CB1 | LD HL,$3000 | Set the x position to 00 and the y position to 30 (3000). | |
| 9CB4 | LD DE,$8367 | Point at the picture (8367). | ||
| 9CB7 | LD C,$4D | Set the attribute of the picture to 4D. | ||
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This entry point is used by the routine at Draw_Right_Wall_Picture.
Fill in the attributes of the picture, 0E rows of three cells.
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| Draw_Wall_Picture | 9CB9 | PUSH HL | Stash the position on the stack. | |
| 9CBA | PUSH DE | Stash the address of the picture on the stack. | ||
| 9CBB | CALL AttributeAddress | Convert the position into an attribute buffer address. | ||
| 9CBE | LD DE,$0020 | Set the size of a row of cells to 20. | ||
| 9CC1 | LD A,C | Copy the attribute to A. | ||
| 9CC2 | LD C,$0E | Set the number of rows to 0E. | ||
| Draw_Left_Wall_Picture_Row_Loop | 9CC4 | PUSH HL | Stash the address of the start of the row on the stack. | |
| 9CC5 | LD B,$03 | Set the number of cells in a row to 03. | ||
| Draw_Left_Wall_Picture_Cell_Loop | 9CC7 | LD (HL),A | Write the attribute to the cell. | |
| 9CC8 | INC L | Move on to the next cell. | ||
| 9CC9 | DJNZ Draw_Left_Wall_Picture_Cell_Loop | Decrease the cell counter and loop back until the row is filled. | ||
| 9CCB | POP HL | Restore the address of the start of the row. | ||
| 9CCC | ADD HL,DE | Move down to the next row. | ||
| 9CCD | DEC C | Decrease the row counter and loop back until all of the rows of attributes are filled. | ||
| 9CCE | JR NZ,Draw_Left_Wall_Picture_Row_Loop | |||
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Copy the pixels of the picture, 70 lines of three bytes.
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| 9CD0 | POP DE | Restore the address of the picture from the stack. | ||
| 9CD1 | POP HL | Restore the position from the stack. | ||
| 9CD2 | CALL ScreenAddress | Convert the position into a screen address. | ||
| 9CD5 | LD C,$70 | Set the number of lines to 70. | ||
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This entry point is used by the routine at Draw_Top_Left_Corner_Picture.
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| Draw_Three_Byte_Lines | 9CD7 | PUSH HL | Stash the screen address of the start of the line on the stack. | |
| 9CD8 | LD B,$03 | Set the number of bytes in a line to 03. | ||
| Draw_Left_Wall_Picture_Byte_Loop | 9CDA | LD A,(DE) | Fetch a byte of the picture. | |
| 9CDB | LD (HL),A | Write it to the screen. | ||
| 9CDC | INC DE | Move on to the next byte of the picture. | ||
| 9CDD | INC L | Move on to the next screen address. | ||
| 9CDE | DJNZ Draw_Left_Wall_Picture_Byte_Loop | Decrease the byte counter and loop back until the line is drawn. | ||
| 9CE0 | POP HL | Restore the screen address of the start of the line. | ||
| 9CE1 | CALL ScreenPosition1PixelBelow | Move down a line. | ||
| 9CE4 | DEC C | Decrease the line counter and loop back until all of the lines of the picture are drawn. | ||
| 9CE5 | JR NZ,Draw_Three_Byte_Lines | |||
| 9CE7 | RET | Return. | ||
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