Routines
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24829: Colour Shelf
Used by the routine at DrawPantry.
Colours the cells of one shelf of the pantry. The cells which have an attribute of 0 are given the colour of the ingredient for the shelf, which was fetched by PantryFillColour. As in DrawShelf there are two sets of attributes; the second is used when the shelf's bit is set in PantryHighlightMask.
Input
B Shelf number
DE Address of the attributes for 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.
ColourShelf 24829 PUSH BC Stash the shelf number and C on the stack.
24830 PUSH DE Stash the address of the normal attributes on the stack.
24831 LD A,B Fetch the shelf number.
24832 RLCA Multiply by 8 so that the shelf number is in bits 3-5.
24833 RLCA
24834 RLCA
24835 AND %00111000 Keep only bits 3-5.
24837 OR %01000111 Set bits 0-2 and bit 6.
24839 LD (24846),A Write A to 24846.
24842 LD A,(24362) 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 stored as BIT 0,A.
ColourShelf_TestBit 24845 BIT 0,A Jump to ColourShelf_Rows if this shelf is not highlighted.
24847 JR Z,ColourShelf_Rows
24849 PUSH HL Move DE on to the highlighted attributes, which are 18 bytes further on (preserving HL).
24850 LD HL,18
24853 ADD HL,DE
24854 EX DE,HL
24855 POP HL
ColourShelf_Rows 24856 LD C,3 Set the number of rows to 3.
ColourShelf_Row 24858 LD B,6 Set the column counter to 6 (the width of the shelf).
24860 PUSH HL Stash the position of the row on the stack.
24861 PUSH BC Stash the counters on the stack.
24862 CALL AttributeAddress Convert the position to an attribute address using AttributeAddress.
24865 POP BC Restore the counters from the stack.
ColourShelf_Loop 24866 LD A,(DE) Fetch the attribute.
24867 AND A Does the attribute need the colour of the ingredient (is it zero)?
24868 CALL Z,FetchShelfColour Call FetchShelfColour if it is, to get the colour of the ingredient.
24871 LD (HL),A Write the attribute to the attribute buffer.
24872 INC DE Move onto the next attribute.
24873 INC HL Move onto the next column.
24874 DJNZ ColourShelf_Loop Decrease the column counter by one and loop back to ColourShelf_Loop until the row has been coloured.
24876 POP HL Restore the position of the row from the stack.
24877 LD A,H Fetch the vertical position of the row.
24878 ADD A,8 Add 8 to move down one row of tiles.
24880 LD H,A Update the vertical position of the row.
24881 DEC C Decrease the row counter by one.
24882 JR NZ,ColourShelf_Row Loop back to ColourShelf_Row until all of the rows have been done.
24884 POP DE Restore the address of the normal attributes from the stack.
24885 POP BC Restore the shelf number and C from the stack.
24886 RET Return.
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