Prev: E461 Up: Map Next: E4A6
E487: Draw Wipe Step
Used by the routines at WipeViewOut and WipeViewIn.
Draws one step of the wipe, by finding the address in the screen buffer with GetBufferAddress and then waiting for the next frame and copying the picture to the screen.
Input
A The step
DrawWipeStep E487 LD H,A A moves into H.
E488 LD L,$10 L is 10.
E48A LD ($5CDA),SP Write SP at SavedStackPointer.
E48E CALL GetBufferAddress Call GetBufferAddress.
E491 HALT Wait for the next frame.
E492 DI Disable interrupts.
E493 LD SP,HL HL moves into SP.
E494 LD DE,$0248 DE is 0248.
DrawWipeStep_Loop E497 DEC DE Step DE back.
E498 LD A,D D moves into A.
E499 OR E Combine A with E.
E49A JR NZ,DrawWipeStep_Loop Jump to E497 if the zero flag is reset.
E49C LD A,($5CD8) Read the byte at ScratchValue.
E49F ADD A,$87 Add 87.
E4A1 CPL Invert the bits of A.
E4A2 LD B,A A moves into B.
E4A3 JP UpdateScreen_Copy Jump to UpdateScreen_Copy.
Prev: E461 Up: Map Next: E4A6