39 lines
1.3 KiB
C
39 lines
1.3 KiB
C
/* ************************************************************************** */
|
|
/* */
|
|
/* ML_horizontal_scroll.c */
|
|
/* | Project : libmonochrome */
|
|
/* */
|
|
/* By: Pierre "PierrotLL" Le Gall <legallpierre89@gmail.com> */
|
|
/* Last updated: 2011/11/22 */
|
|
/* */
|
|
/* ************************************************************************** */
|
|
|
|
#include <monochrome/internals.h>
|
|
|
|
void ML_horizontal_scroll(int scroll)
|
|
{
|
|
int i, j;
|
|
char line[16], shift, *vram;
|
|
unsigned char next;
|
|
unsigned short word;
|
|
vram = ML_vram_address();
|
|
scroll %= 128;
|
|
shift = 8-(scroll&7);
|
|
for(i=0 ; i<64 ; i++)
|
|
{
|
|
for(j=0 ; j<16 ; j++) line[j] = vram[(i<<4)+((j-(scroll>>3)+15)&15)];
|
|
next = line[15];
|
|
vram[(i<<4)+15] = 0;
|
|
for(j=15 ; j>0 ; j--)
|
|
{
|
|
word = next << shift;
|
|
next = line[j-1];
|
|
vram[(i<<4)+j] |= *((char*)&word+1);
|
|
vram[(i<<4)+j-1] = *((char*)&word);
|
|
}
|
|
word = next << shift;
|
|
vram[(i<<4)] |= *((char*)&word+1);
|
|
vram[(i<<4)+15] |= *((char*)&word);
|
|
}
|
|
}
|