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apple2_hgr_font_tutorial
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Fix bad syntax in pseudo code

This commit is contained in:
Michaelangel007 2016-08-03 12:36:57 -07:00
parent e396be0515
commit 9cb645ec4c
1 changed files with 8 additions and 4 deletions
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README.md
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@ -1,7 +1,7 @@
#Apple ]\[ //e HGR Font 6502 Assembly Language Tutorial
By: Michael Pohoreski
Revision: 70, Mar 27, 2016.
Revision: 71, Mar 27, 2016.
# Table of Contents
@ -3015,7 +3015,7 @@ Seriously though, start with the data flow. Let's look at the HGR "text" lines w
We need to copy 23 HGR "text" lines to the one above; we also need to clear the bottom row. Pseudo-code would be:
```C
for( int line = 0; line < 24-1; line++
for( int line = 0; line < 24-1; line++ )
copy_line( line+1, line );
clear_line( 23 );
```
@ -3023,18 +3023,21 @@ We need to copy 23 HGR "text" lines to the one above; we also need to clear the
Each HGR "text" line takes up 40 columns
```C
for( int row = 0; row < 23; row++
for( int row = 0; row < 23; row++ )
{
char *src = HGRAddressY[ row + 1 ]
char *dst = HGRAddressY[ row + 0 ]
for( int col = 0; col < 40; col++ )
*dst++ = *src++;
}
clear_line( 23 );
```
However each HGR "text" line takes 8 scanlines (since our font cell is 7x8).
```C
for( row = 0; row < 23; row++
for( row = 0; row < 23; row++ )
{
char *src = HGRAddressY[ row + 1 ]
char *dst = HGRAddressY[ row + 0 ]
for( line = 0; line < 8; line++ )
@ -3044,6 +3047,7 @@ However each HGR "text" line takes 8 scanlines (since our font cell is 7x8).
src += 0x400;
dst += 0x400;
}
}
```
We could code this up as: