Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-10-05 08:41:31 +03:00
Code Issues Actions 3 Packages Projects Releases Wiki Activity

Improve Osborne 1 scroll behaviour based on reading schematic

Browse Source
This commit is contained in:
Vas Crabb 2015-10-27 17:29:24 +11:00
parent c57130f22f
commit 384fdb4f1d
2 changed files with 13 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/mame/includes/osborne1.h
View File

@ -96,6 +96,7 @@ public:
/* video related */
UINT8 m_screen_pac;
UINT8 m_resolution;
UINT8 m_hc_left;
UINT8 m_new_start_x;
UINT8 m_new_start_y;
emu_timer *m_video_timer;

23
src/mame/machine/osborne1.c
View File

@ -113,6 +113,7 @@ WRITE8_MEMBER( osborne1_state::osborne1_2000_w )
break;
case 0x400: /* SCREEN-PAC */
m_resolution = data & 0x01;
m_hc_left = (data >> 1) & 0x01;
break;
case 0x900: /* IEEE488 PIA */
m_pia0->write(space, offset & 0x03, data );
@ -342,9 +343,8 @@ void osborne1_state::device_timer(emu_timer &timer, device_timer_id id, int para
TIMER_CALLBACK_MEMBER(osborne1_state::osborne1_video_callback)
{
int y = machine().first_screen()->vpos();
UINT8 ra=0,chr,gfx,dim;
UINT16 x,ma;
int const y = machine().first_screen()->vpos();
UINT8 ra=0;
/* Check for start of frame */
if ( y == 0 )
@ -361,18 +361,18 @@ TIMER_CALLBACK_MEMBER(osborne1_state::osborne1_video_callback)
{
ra = y % 10;
/* Draw a line of the display */
ma = (m_new_start_y + (y/10)) * 128 + m_new_start_x;
bool const hires = m_screen_pac & m_resolution;
UINT16 const row = (m_new_start_y + (y/10)) * 128 & 0xF80;
UINT16 const col = (m_new_start_x & (hires ? 0x60 : 0x7F));
UINT16 *p = &m_bitmap.pix16(y);
for ( x = 0; x < ((m_screen_pac && m_resolution) ? 104 : 52); x++ )
for ( UINT16 x = 0; x < ((m_screen_pac && m_resolution) ? 104 : 52); x++ )
{
chr = m_ram->pointer()[ 0xF000 + ( (ma+x) & 0xFFF ) ];
dim = m_ram->pointer()[ 0x10000 + ( (ma+x) & 0xFFF ) ] & 0x80;
UINT16 offs = row | ((col + x) & 0x7F);
UINT8 const chr = m_ram->pointer()[ 0xF000 + offs ];
UINT8 const dim = m_ram->pointer()[ 0x10000 + offs ] & 0x80;
if ( (chr & 0x80) && (ra == 9) )
gfx = 0xFF;
else
gfx = m_p_chargen[ (ra << 7) | ( chr & 0x7F ) ];
UINT8 const gfx = ((chr & 0x80) && (ra == 9)) ? 0xFF : m_p_chargen[ (ra << 7) | (chr & 0x7F) ];
/* Display a scanline of a character */
*p++ = BIT(gfx, 7) ? ( dim ? 2 : 1 ) : 0;
@ -425,6 +425,7 @@ void osborne1_state::machine_reset()
m_screen_pac = 0 != (m_cnf->read() & 0x01);
m_resolution = 0;
m_hc_left = 0;
m_p_chargen = memregion( "chargen" )->base();
memset( m_ram->pointer() + 0x10000, 0xFF, 0x1000 );