Blkdestheight – Cirrus Logic EP93xx User Manual

Page 292

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DS785UM1

Copyright 2007 Cirrus Logic

Graphics Accelerator
EP93xx User’s Guide

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For Line Draw functions, the method to determine the
value of WIDTH is dependent on the line draw algorithm.
For the Burnishing algorithm, please refer to
BLKDESTWIDTH in

Section 8.6.1 on page 8-13

. For the

DX/DY algorithm, please refer to BLKDESTWIDTH in

Section 8.6.3 on page 8-16

. The value of WIDTH is

multiplied by the value of HEIGHT in the

BLKDESTHEIGHT

register to determine the number of

line draw iterations.

BLKDESTHEIGHT

Address:

0x8004_001C - Read/Write

Default:

0x0000_0000

Mask:

0x0000_07FF

Definition:

Block Function Destination Height Register

Bit Descriptions:

RSVD:

Reserved - Unknown during read

HEIGHT:

Height - Read/Write

For Block Fill or Block Copy functions, the value in this
field specifies the height in ‘lines minus 1’ of the
destination image. Since there is no BLKSRCHEIGHT
register, the source image must have the same height as
the destination image.

For Line Draw functions, the value in this field specifies the
distance in ‘lines minus 1’ between Y_dest_end and
Y_dest_start. The method to determine the value of
HEIGHT is dependent on the line draw algorithm. For the
Breshenham algorithm, please refer to BLKDESTHEIGHT
in

Section 8.6.1 on page 8-13

.

The value of HEIGHT is

multiplied by the value of WIDTH in the

BLKDESTWIDTH

register to determine the number of line draw iterations.

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RSVD

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2

1

0

RSVD

HEIGHT

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