Gunfright: Routine at CD8C

CD8C: Test Move

Used by the routines at HandleOutlaw, HandleBystander, HandleBullet, MovePlayerForward and CheckWallsEachWay.

Checks whether an object can move in the direction of its heading without going into a wall. A wall changes the speeds so that the object stops, and sets bit 0 of the flags.

Input
IX	The address of the object

Output
F	The carry flag is set if the object hit a wall

Clear bit 0 of the flags, then run the routine for the heading.

TestMove

CD8C

RES 0,(IX+$07)

Clear bit 0 of the flags of the object.

This entry point is used by the routines at HandleBullet and CheckWallsEachWay.

Run the routine for the heading, without clearing the flag.

CheckWalls

CD90

LD A,(IX+$06)

Fetch the heading.

CD93

RLCA

Move the heading into the lowest two bits.

CD94

RLCA

CD95

AND %00000011

Keep only the heading.

CD97

LD BC,$CD9D

Point BC at CheckWallsRoutines.

CD9A

JP RunTableRoutine

Jump to RunTableRoutine.

View the equivalent code in;

Nightshade