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Routines |
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36796 | LD A,(34256) | Pick up Willy's direction and movement flags from 34256 | |||||
36799 | AND 2 | Is Willy moving? | |||||
36801 | RET Z | Return if not | |||||
36802 | LD A,(34262) | Pick up the rope status indicator from 34262 | |||||
36805 | DEC A | Is Willy on a rope? | |||||
36806 | BIT 7,A | ||||||
36808 | RET Z | Return if so (Willy's movement along a rope is handled at 37726) | |||||
36809 | LD A,(34256) | Pick up Willy's direction and movement flags from 34256 | |||||
36812 | AND 1 | Is Willy facing right? | |||||
36814 | JP Z,36930 | Jump if so | |||||
Willy is moving left.
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36817 | LD A,(34258) | Pick up Willy's animation frame from 34258 | |||||
36820 | OR A | Is it 0? | |||||
36821 | JR Z,36828 | If so, jump to move Willy's sprite left across a cell boundary | |||||
36823 | DEC A | Decrement Willy's animation frame at 34258 | |||||
36824 | LD (34258),A | ||||||
36827 | RET | ||||||
Willy's sprite is moving left across a cell boundary. In the comments that follow, (x,y) refers to the coordinates of the top-left cell currently occupied by Willy's sprite.
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36828 | LD A,(34257) | Pick up the airborne status indicator from 34257 | |||||
36831 | LD BC,0 | Prepare BC for later addition | |||||
36834 | CP 0 | Is Willy jumping? | |||||
36836 | JR NZ,36874 | Jump if so | |||||
36838 | LD HL,(34259) | Collect Willy's attribute buffer coordinates from 34259 | |||||
36841 | LD BC,0 | Prepare BC for later addition (again, redundantly) | |||||
36844 | LD A,(32986) | Pick up the direction byte of the ramp definition for the current room from 32986 | |||||
36847 | DEC A | Now A=31 if the ramp goes up to the left, or 65 if it goes up to the right | |||||
36848 | OR 161 | ||||||
36850 | XOR 224 | ||||||
36852 | LD E,A | Point HL at the cell at (x-1,y+1) if the ramp goes up to the left, or at the cell at (x+1,y+2) if the ramp goes up to the right | |||||
36853 | LD D,0 | ||||||
36855 | ADD HL,DE | ||||||
36856 | LD A,(32964) | Pick up the attribute byte of the ramp tile for the current room from 32964 | |||||
36859 | CP (HL) | Is there a ramp tile in the cell pointed to by HL? | |||||
36860 | JR NZ,36874 | Jump if not | |||||
36862 | LD BC,32 | Prepare BC for later addition | |||||
36865 | LD A,(32986) | Pick up the direction byte of the ramp definition for the current room from 32986 | |||||
36868 | OR A | Does the ramp go up to the right? | |||||
36869 | JR NZ,36874 | Jump if so | |||||
36871 | LD BC,65504 | BC=-32 (the ramp goes up to the left) | |||||
36874 | LD HL,(34259) | Collect Willy's attribute buffer coordinates from 34259 | |||||
36877 | LD A,L | Is Willy's screen x-coordinate 0 (on the far left)? | |||||
36878 | AND 31 | ||||||
36880 | JP Z,38026 | If so, move Willy into the room to the left | |||||
36883 | ADD HL,BC | Point HL at the cell at (x-1,y+1), or at the cell at (x-1,y) if Willy is on or about to step onto a ramp that goes up to the left, or at the cell at (x-1,y+2) if Willy is walking down a ramp | |||||
36884 | DEC HL | ||||||
36885 | LD DE,32 | ||||||
36888 | ADD HL,DE | ||||||
36889 | LD A,(32946) | Pick up the attribute byte of the wall tile for the current room from 32946 | |||||
36892 | CP (HL) | Is there a wall tile in the cell pointed to by HL? | |||||
36893 | RET Z | Return if so without moving Willy (his path is blocked) | |||||
36894 | LD A,(34255) | Pick up Willy's pixel y-coordinate (Y) from 34255 | |||||
36897 | SRA C | Now B=Y (if Willy is neither on nor about to step onto a ramp), or Y+16 (if Willy is walking down a ramp), or Y-16 (if Willy is on or about to step onto a ramp that goes up to the left); this will be Willy's new pixel y-coordinate | |||||
36899 | ADD A,C | ||||||
36900 | LD B,A | ||||||
36901 | AND 15 | Is Willy at a point in a jump (left) where his sprite occupies three rows of cells? | |||||
36903 | JR Z,36914 | Jump if not (Willy's sprite is cell-aligned) | |||||
36905 | LD A,(32946) | Pick up the attribute byte of the wall tile for the current room from 32946 | |||||
36908 | ADD HL,DE | Point HL at the cell at (x-1,y+2) | |||||
36909 | CP (HL) | Is there a wall tile there? | |||||
36910 | RET Z | Return if so without moving Willy (his path is blocked) | |||||
36911 | OR A | Point HL at the cell at (x-1,y+1) | |||||
36912 | SBC HL,DE | ||||||
36914 | OR A | Point HL at the cell at (x-1,y), or at the cell at (x-1,y-1) if Willy is on or about to step onto a ramp that goes up to the left, or at the cell at (x-1,y+1) if Willy is walking down a ramp | |||||
36915 | SBC HL,DE | ||||||
36917 | LD (34259),HL | Save Willy's new attribute buffer coordinates (in HL) at 34259 | |||||
36920 | LD A,B | Save Willy's new pixel y-coordinate at 34255 | |||||
36921 | LD (34255),A | ||||||
36924 | LD A,3 | Change Willy's animation frame at 34258 from 0 to 3 | |||||
36926 | LD (34258),A | ||||||
36929 | RET | ||||||
Willy is moving right.
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36930 | LD A,(34258) | Pick up Willy's animation frame from 34258 | |||||
36933 | CP 3 | Is it 3? | |||||
36935 | JR Z,36942 | If so, jump to move Willy's sprite right across a cell boundary | |||||
36937 | INC A | Increment Willy's animation frame at 34258 | |||||
36938 | LD (34258),A | ||||||
36941 | RET | ||||||
Willy's sprite is moving right across a cell boundary. In the comments that follow, (x,y) refers to the coordinates of the top-left cell currently occupied by Willy's sprite.
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36942 | LD A,(34257) | Pick up the airborne status indicator from 34257 | |||||
36945 | LD BC,0 | Prepare BC for later addition | |||||
36948 | OR A | Is Willy jumping? | |||||
36949 | JR NZ,36984 | Jump if so | |||||
36951 | LD HL,(34259) | Collect Willy's attribute buffer coordinates from 34259 | |||||
36954 | LD A,(32986) | Pick up the direction byte of the ramp definition for the current room from 32986 | |||||
36957 | DEC A | Now A=64 if the ramp goes up to the left, or 34 if it goes up to the right | |||||
36958 | OR 157 | ||||||
36960 | XOR 191 | ||||||
36962 | LD E,A | Point HL at the cell at (x,y+2) if the ramp goes up to the left, or at the cell at (x+2,y+1) if the ramp goes up to the right | |||||
36963 | LD D,0 | ||||||
36965 | ADD HL,DE | ||||||
36966 | LD A,(32964) | Pick up the attribute byte of the ramp tile for the current room from 32964 | |||||
36969 | CP (HL) | Is there a ramp tile in the cell pointed to by HL? | |||||
36970 | JR NZ,36984 | Jump if not | |||||
36972 | LD BC,32 | Prepare BC for later addition | |||||
36975 | LD A,(32986) | Pick up the direction byte of the ramp definition for the current room from 32986 | |||||
36978 | OR A | Does the ramp go up to the left? | |||||
36979 | JR Z,36984 | Jump if so | |||||
36981 | LD BC,65504 | BC=-32 (the ramp goes up to the right) | |||||
36984 | LD HL,(34259) | Collect Willy's attribute buffer coordinates from 34259 | |||||
36987 | ADD HL,BC | Point HL at the cell at (x+2,y), or at the cell at (x+2,y+1) if Willy is walking down a ramp, or at the cell at (x+2,y-1) if Willy is on or about to step onto a ramp that goes up to the right | |||||
36988 | INC HL | ||||||
36989 | INC HL | ||||||
36990 | LD A,L | Is Willy's screen x-coordinate 30 (on the far right)? | |||||
36991 | AND 31 | ||||||
36993 | JP Z,38046 | If so, move Willy into the room on the right | |||||
36996 | LD DE,32 | Prepare DE for addition | |||||
36999 | LD A,(32946) | Pick up the attribute byte of the wall tile for the current room from 32946 | |||||
37002 | ADD HL,DE | Point HL at the cell at (x+2,y+1), or at the cell at (x+2,y+2) if Willy is walking down a ramp, or at the cell at (x+2,y) if Willy is on or about to step onto a ramp that goes up to the right | |||||
37003 | CP (HL) | Is there a wall tile in the cell pointed to by HL? | |||||
37004 | RET Z | Return if so without moving Willy (his path is blocked) | |||||
37005 | LD A,(34255) | Pick up Willy's pixel y-coordinate (Y) from 34255 | |||||
37008 | SRA C | Now B=Y (if Willy is neither on nor about to step onto a ramp), or Y+16 (if Willy is walking down a ramp), or Y-16 (if Willy is on or about to step onto a ramp that goes up to the right); this will be Willy's new pixel y-coordinate | |||||
37010 | ADD A,C | ||||||
37011 | LD B,A | ||||||
37012 | AND 15 | Is Willy at a point in a jump (right) where his sprite occupies three rows of cells? | |||||
37014 | JR Z,37025 | Jump if not (Willy's sprite is cell-aligned) | |||||
37016 | LD A,(32946) | Pick up the attribute byte of the wall tile for the current room from 32946 | |||||
37019 | ADD HL,DE | Point HL at the cell at (x+2,y+2) | |||||
37020 | CP (HL) | Is there a wall tile there? | |||||
37021 | RET Z | Return if so without moving Willy (his path is blocked) | |||||
37022 | OR A | Point HL at the cell at (x+2,y+1) | |||||
37023 | SBC HL,DE | ||||||
37025 | LD A,(32946) | Pick up the attribute byte of the wall tile for the current room from 32946 | |||||
37028 | OR A | Point HL at the cell at (x+2,y), or at the cell at (x+2,y+1) if Willy is walking down a ramp, or at the cell at (x+2,y-1) if Willy is on or about to step onto a ramp that goes up to the right | |||||
37029 | SBC HL,DE | ||||||
37031 | CP (HL) | Is there a wall tile in the cell pointed to by HL? | |||||
37032 | RET Z | Return if so without moving Willy (his path is blocked) | |||||
37033 | DEC HL | Point HL at the cell at (x+1,y), or at the cell at (x+1,y+1) if Willy is walking down a ramp, or at the cell at (x+1,y-1) if Willy is on or about to step onto a ramp that goes up to the right | |||||
37034 | LD (34259),HL | Save Willy's new attribute buffer coordinates (in HL) at 34259 | |||||
37037 | XOR A | Change Willy's animation frame at 34258 from 3 to 0 | |||||
37038 | LD (34258),A | ||||||
37041 | LD A,B | Save Willy's new pixel y-coordinate at 34255 | |||||
37042 | LD (34255),A | ||||||
37045 | RET |
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