Agnus/ Read/ Denise/ Register Address Write Paula Function -------- ------- ----- ------- -------- BLTxMOD 064 W A Blitter modulo x This register contains the modulo for blitter source (x=A,B,C) or destination (x=D). A modulo is a number that is automatically added to the address at the end of each line, to make the address point to the start of the next line. Each source or destination has its own modulo, allowing each to be a different size, while an identical area of each is used in the blitter operation. LINE DRAW BLTAMOD and BLTBMOD are used as slope LINE DRAW storage registers and must be preloaded LINE DRAW with the values (4Y-4X) and (4Y) LINE DRAW respectively. Y/X= line slope. LINE DRAW BLTCMOD and BLTDMOD must both be LINE DRAW preloaded with the width (in bytes) LINE DRAW of the image into which the line is LINE DRAW being drawn (normally two times the LINE DRAW screen width in words).
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