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Routines |
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Draws the columns of a sprite which is flipped and shifted. There is a piece of code for each of up to five columns of the sprite, and the code for the width of the sprite is where the jump at SpriteJumpOpcode starts. Each piece puts a column into two bytes of the buffer, using the table for the shift to turn the mask and the pixels round and split them in two. It works from right to left.
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The jump at SpriteJumpOpcode starts here for five columns.
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| DrawFlippedShiftedColumns | 49115 | CPL | Invert the screen byte. | |
| 49116 | POP DE | Restore the mask into E and the pixels into D from the stack. | ||
| 49117 | LD L,E | Clear the screen bits under the part of the mask which is in this byte. | ||
| 49118 | OR (HL) | |||
| 49119 | CPL | |||
| 49120 | LD L,D | Add the part of the pixels which is in this byte. | ||
| 49121 | OR (HL) | |||
| 49122 | LD (BC),A | Store the byte and move on to the byte on the left. | ||
| 49123 | DEC BC | |||
| 49124 | DEC H | Point H at the table for the bits which move into the next byte, and fetch that screen byte. | ||
| 49125 | LD L,E | |||
| 49126 | LD A,(BC) | |||
| 49127 | CPL | Clear the screen bits under the part of the mask which has moved into it. | ||
| 49128 | OR (HL) | |||
| 49129 | CPL | |||
| 49130 | LD L,D | Add the part of the pixels which has moved into it. | ||
| 49131 | OR (HL) | |||
| 49132 | INC H | Point H back at the first table. | ||
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The jump at SpriteJumpOpcode starts here for four columns.
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| 49133 | CPL | Invert the screen byte. | ||
| 49134 | POP DE | Restore the mask into E and the pixels into D from the stack. | ||
| 49135 | LD L,E | Clear the screen bits under the part of the mask which is in this byte. | ||
| 49136 | OR (HL) | |||
| 49137 | CPL | |||
| 49138 | LD L,D | Add the part of the pixels which is in this byte. | ||
| 49139 | OR (HL) | |||
| 49140 | LD (BC),A | Store the byte and move on to the byte on the left. | ||
| 49141 | DEC BC | |||
| 49142 | DEC H | Point H at the table for the bits which move into the next byte, and fetch that screen byte. | ||
| 49143 | LD L,E | |||
| 49144 | LD A,(BC) | |||
| 49145 | CPL | Clear the screen bits under the part of the mask which has moved into it. | ||
| 49146 | OR (HL) | |||
| 49147 | CPL | |||
| 49148 | LD L,D | Add the part of the pixels which has moved into it. | ||
| 49149 | OR (HL) | |||
| 49150 | INC H | Point H back at the first table. | ||
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The jump at SpriteJumpOpcode starts here for three columns.
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| 49151 | CPL | Invert the screen byte. | ||
| 49152 | POP DE | Restore the mask into E and the pixels into D from the stack. | ||
| 49153 | LD L,E | Clear the screen bits under the part of the mask which is in this byte. | ||
| 49154 | OR (HL) | |||
| 49155 | CPL | |||
| 49156 | LD L,D | Add the part of the pixels which is in this byte. | ||
| 49157 | OR (HL) | |||
| 49158 | LD (BC),A | Store the byte and move on to the byte on the left. | ||
| 49159 | DEC BC | |||
| 49160 | DEC H | Point H at the table for the bits which move into the next byte, and fetch that screen byte. | ||
| 49161 | LD L,E | |||
| 49162 | LD A,(BC) | |||
| 49163 | CPL | Clear the screen bits under the part of the mask which has moved into it. | ||
| 49164 | OR (HL) | |||
| 49165 | CPL | |||
| 49166 | LD L,D | Add the part of the pixels which has moved into it. | ||
| 49167 | OR (HL) | |||
| 49168 | INC H | Point H back at the first table. | ||
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The jump at SpriteJumpOpcode starts here for two columns.
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| 49169 | CPL | Invert the screen byte. | ||
| 49170 | POP DE | Restore the mask into E and the pixels into D from the stack. | ||
| 49171 | LD L,E | Clear the screen bits under the part of the mask which is in this byte. | ||
| 49172 | OR (HL) | |||
| 49173 | CPL | |||
| 49174 | LD L,D | Add the part of the pixels which is in this byte. | ||
| 49175 | OR (HL) | |||
| 49176 | LD (BC),A | Store the byte and move on to the byte on the left. | ||
| 49177 | DEC BC | |||
| 49178 | DEC H | Point H at the table for the bits which move into the next byte, and fetch that screen byte. | ||
| 49179 | LD L,E | |||
| 49180 | LD A,(BC) | |||
| 49181 | CPL | Clear the screen bits under the part of the mask which has moved into it. | ||
| 49182 | OR (HL) | |||
| 49183 | CPL | |||
| 49184 | LD L,D | Add the part of the pixels which has moved into it. | ||
| 49185 | OR (HL) | |||
| 49186 | INC H | Point H back at the first table. | ||
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The jump at SpriteJumpOpcode starts here for one column.
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| 49187 | CPL | Invert the screen byte. | ||
| 49188 | POP DE | Restore the mask into E and the pixels into D from the stack. | ||
| 49189 | LD L,E | Clear the screen bits under the part of the mask which is in this byte. | ||
| 49190 | OR (HL) | |||
| 49191 | CPL | |||
| 49192 | LD L,D | Add the part of the pixels which is in this byte. | ||
| 49193 | OR (HL) | |||
| 49194 | LD (BC),A | Store the byte and move on to the byte on the left. | ||
| 49195 | DEC BC | |||
| 49196 | DEC H | Point H at the table for the bits which move into the next byte, and fetch that screen byte. | ||
| 49197 | LD L,E | |||
| 49198 | LD A,(BC) | |||
| 49199 | CPL | Clear the screen bits under the part of the mask which has moved into it. | ||
| 49200 | OR (HL) | |||
| 49201 | CPL | |||
| 49202 | LD L,D | Add the part of the pixels which has moved into it. | ||
| 49203 | OR (HL) | |||
| 49204 | INC H | Point H back at the first table. | ||
| 49205 | LD (BC),A | Store the last byte of the row. | ||
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Continue on to FinishFlippedSpriteRow.
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| Prev: 49110 | Up: Map | Next: 49206 |