Routines
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60BD: Draw Shelf
Used by the routine at DrawPantry.
Draws the tiles for one shelf of the pantry. A shelf is 06 tiles wide and 03 tiles tall. There are two graphics for a shelf; the normal one and the highlighted one, which is used when the shelf's bit is set in PantryHighlightMask. The example below is for the top shelf (shelf 05). Its colours are set first, so that the tiles can be seen.
Before After
draw-shelf-before draw-shelf-after
Input
B Shelf number
DE Address of the normal graphic
HL Position of the shelf
Output
HL Position of the shelf below
Make the second byte of a BIT command from the shelf number.
DrawShelf 60BD PUSH BC Stash the shelf number and C on the stack.
60BE PUSH DE Stash the address of the normal graphic on the stack.
60BF LD A,B Fetch the shelf number.
60C0 RLCA Multiply by 08 so that the shelf number is in bits 3-5.
60C1 RLCA
60C2 RLCA
60C3 AND %00111000 Keep only bits 3-5.
60C5 OR %01000111 Set bits 0-2 and bit 6.
60C7 LD ($60CE),A Write A to 60CE.
60CA LD A,($5F2A) Fetch the mask of the highlighted shelf.
Self modifying code; the command which is here is made into BIT n,A, where n is the shelf number, by the instructions above. It is shown as RLC B as that is how it is stored.
DrawShelf_TestBit 60CD RLC B Test the bit for the shelf in the mask.
60CF JR Z,DrawShelf_Print Jump to DrawShelf_Print if this shelf is not highlighted.
60D1 PUSH HL Move DE on to the highlighted graphic, which is 12 bytes further on (preserving HL).
60D2 LD HL,$0012
60D5 ADD HL,DE
60D6 EX DE,HL
60D7 POP HL
DrawShelf_Print 60D8 LD C,$03 Set the number of rows to 03.
60DA LD A,$06 Set the width to 06 tiles.
60DC CALL PrintTileBlock Print the tiles for the shelf using PrintTileBlock.
60DF POP DE Restore the address of the normal graphic from the stack.
60E0 POP BC Restore the shelf number and C from the stack.
60E1 RET Return.
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