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bbc: minor video improvements

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- fixed cursor size
- double clock in MODE7 to counteract non-implemented interlace
This commit is contained in:
Nigel Barnes 2017-08-26 16:49:58 +01:00
parent ae687c0e7a
commit 9e1b2200ad
2 changed files with 88 additions and 120 deletions
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49
src/mame/includes/bbc.h
View File

@ -399,42 +399,27 @@ public: // HACK FOR MC6845
// this is the real location of the start of the BBC's ram in the emulation
// it can be changed if shadow ram is being used to point at the upper 32K of RAM
// this is the screen memory location of the next pixels to be drawn
// this is a more global variable to store the bitmap variable passed in in the bbc_vh_screenrefresh function
// this is the X and Y screen location in emulation pixels of the next pixels to be drawn
unsigned char *m_BBC_Video_RAM;
uint16_t *m_BBC_display;
uint16_t *m_BBC_display_left;
uint16_t *m_BBC_display_right;
bitmap_ind16 *m_BBC_bitmap;
int m_y_screen_pos;
unsigned char m_pixel_bits[256];
uint8_t *m_video_ram;
uint8_t m_pixel_bits[256];
int m_hsync;
int m_vsync;
int m_display_enable;
int m_Teletext_Latch;
int m_VideoULA_CR;
int m_VideoULA_CR_counter;
int m_videoULA_Reg;
int m_videoULA_master_cursor_size;
int m_videoULA_width_of_cursor;
int m_videoULA_6845_clock_rate;
int m_videoULA_characters_per_line;
int m_videoULA_teletext_normal_select;
int m_videoULA_flash_colour_select;
uint8_t m_teletext_latch;
struct {
// control register
int master_cursor_size;
int width_of_cursor;
int clock_rate_6845;
int characters_per_line;
int teletext_normal_select;
int flash_colour_select;
// inputs
int de;
} m_video_ula;
int m_pixels_per_byte;
int m_emulation_pixels_per_real_pixel;
int m_emulation_pixels_per_byte;
int m_emulation_cursor_size;
int m_cursor_state;
int m_cursor_size;
int m_videoULA_palette0[16];
int m_videoULA_palette1[16];
@ -452,7 +437,7 @@ public: // HACK FOR MC6845
void MC6850_Receive_Clock(int new_clock);
void BBC_Cassette_motor(unsigned char status);
void bbc_update_nmi();
unsigned int calculate_video_address(int ma,int ra);
uint16_t calculate_video_address(uint16_t ma, uint8_t ra);
required_device<palette_device> m_palette;
optional_ioport m_bbcconfig;
};

159
src/mame/video/bbc.cpp
View File

@ -37,23 +37,21 @@
* the output of S4 is linked out to a 0v supply by link S25 to just access the 16K memory area.
************************************************************************/
unsigned int bbc_state::calculate_video_address(int ma,int ra)
uint16_t bbc_state::calculate_video_address(uint16_t ma, uint8_t ra)
{
// ma = output from IC2 6845 MA address
int c0 = m_b4_video0; // output from IC32 74LS259 bits 4 and 5
/* output from IC32 74LS259 bits 4 and 5 */
int c0 = m_b4_video0;
int c1 = m_b5_video1;
/* the 4 bit input port b on IC39 are produced by 4 NAND gates.
these NAND gates take their
inputs from c0 and c1 (from IC32) and ma12 (from the 6845) */
/* the 4 bit input port b on IC39 are produced by 4 NAND gates. These NAND gates take their inputs
from c0 and c1 (from IC32) and ma12 (from the 6845) */
/* get bit m12 from the 6845 */
int ma12 = BIT(ma,12);
int ma12 = BIT(ma, 12);
// 4 bit input B on IC39 74LS283 (4 bit adder)
/* 4 bit input B on IC39 74LS283 (4 bit adder) */
/* 3 input NAND part of IC 36 */
int b1=(~(c1 & c0 & ma12)) & 1;
int b1 = (~(c1 & c0 & ma12)) & 1;
/* 2 input NAND part of IC40 (b3 is calculated before b2 and b4 because b3 feed back into b2 and b4) */
int b3 = (~(c0 & ma12)) & 1;
/* 3 input NAND part of IC 36 */
@ -73,17 +71,13 @@ unsigned int bbc_state::calculate_video_address(int ma,int ra)
/* if MA13 (TTXVDU) is low then IC8 and IC9 are used to calculate
the memory location required for the hi res video.
if MA13 is high then IC10 and IC11 are used to calculate the memory location for the teletext chip */
unsigned int m;
if (BIT(ma,13))
{
// IC 10 and IC 11
uint16_t m;
if (BIT(ma, 13))
m = ((ma & 0x3ff) | 0x3c00) | ((s & 0x8)<<11);
} else {
// IC 8 and IC 9
else
m = ((ma & 0xff)<<3) | (s<<11) | (ra & 0x7);
}
if (m_memorySize == 16)
return m & 0x3fff;
if (m_memorySize == 16) m &= 0x3fff;
return m;
}
@ -149,50 +143,52 @@ void bbc_state::set_pixel_lookup()
WRITE8_MEMBER(bbc_state::bbc_videoULA_w)
{
// Make sure vpos is never <0 2008-10-11 PHS.
int vpos=machine().first_screen()->vpos();
if(vpos==0)
// Make sure vpos is never <0
int vpos = machine().first_screen()->vpos();
if (vpos == 0)
machine().first_screen()->update_partial(vpos);
else
machine().first_screen()->update_partial(vpos -1 );
machine().first_screen()->update_partial(vpos - 1);
logerror("setting videoULA %.4x to:%.4x at :%d \n",data,offset,machine().first_screen()->vpos() );
switch (offset&0x01)
switch (offset & 0x01)
{
// Set the control register in the Video ULA
case 0:
m_videoULA_Reg = data;
m_videoULA_master_cursor_size = BIT(m_videoULA_Reg,7);
m_videoULA_width_of_cursor = (m_videoULA_Reg>>5)&0x03;
m_videoULA_6845_clock_rate = BIT(m_videoULA_Reg,4);
m_videoULA_characters_per_line = (m_videoULA_Reg>>2)&0x03;
m_videoULA_teletext_normal_select = BIT(m_videoULA_Reg,1);
m_videoULA_flash_colour_select = BIT(m_videoULA_Reg,0);
m_video_ula.master_cursor_size = BIT(data, 7);
m_video_ula.width_of_cursor = (data >> 5) & 0x03;
m_video_ula.clock_rate_6845 = BIT(data, 4);
m_video_ula.characters_per_line = (data >> 2) & 0x03;
m_video_ula.teletext_normal_select = BIT(data, 1);
m_video_ula.flash_colour_select = BIT(data, 0);
m_videoULA_palette_lookup = m_videoULA_flash_colour_select ? m_videoULA_palette0 : m_videoULA_palette1;
m_videoULA_palette_lookup = m_video_ula.flash_colour_select ? m_videoULA_palette0 : m_videoULA_palette1;
m_emulation_cursor_size = width_of_cursor_set[m_videoULA_width_of_cursor | (m_videoULA_master_cursor_size<<2)];
m_cursor_size = width_of_cursor_set[m_video_ula.width_of_cursor | (m_video_ula.master_cursor_size << 2)];
// this is the number of BBC pixels held in each byte
if (m_videoULA_teletext_normal_select)
if (m_video_ula.teletext_normal_select)
m_pixels_per_byte = 12;
else
m_pixels_per_byte = pixels_per_byte_set[m_videoULA_characters_per_line | (m_videoULA_6845_clock_rate<<2)];
m_pixels_per_byte = pixels_per_byte_set[m_video_ula.characters_per_line | (m_video_ula.clock_rate_6845 << 2)];
m_hd6845->set_hpixels_per_column(m_pixels_per_byte);
if (m_videoULA_6845_clock_rate)
m_hd6845->set_clock(XTAL_16MHz/8);
if (m_video_ula.clock_rate_6845)
m_hd6845->set_clock(XTAL_16MHz / 8);
else
m_hd6845->set_clock(XTAL_16MHz/16);
m_hd6845->set_clock(XTAL_16MHz / 16);
// FIXME: double clock for MODE7 until interlace is implemented
if (m_video_ula.teletext_normal_select)
m_hd6845->set_clock(XTAL_16MHz / 8);
break;
// Set a palette register in the Video ULA
case 1:
int tpal = (data >> 4) & 0x0f;
int tcol = data & 0x0f;
uint8_t tpal = (data >> 4) & 0x0f;
uint8_t tcol = data & 0x0f;
m_videoULA_palette0[tpal] = tcol;
m_videoULA_palette1[tpal] = tcol<8 ? tcol : tcol^7;
m_videoULA_palette1[tpal] = tcol<8 ? tcol : tcol ^ 7;
break;
}
}
@ -205,37 +201,33 @@ MC6845_UPDATE_ROW( bbc_state::crtc_update_row )
{
const rgb_t *palette = m_palette->palette()->entry_list_raw();
if (m_videoULA_teletext_normal_select)
if (m_video_ula.teletext_normal_select)
{
m_trom->lose_w(1);
m_trom->lose_w(0);
for(int x_pos=0; x_pos<x_count; x_pos++)
for (int x_pos = 0; x_pos < x_count; x_pos++)
{
//Teletext Latch bits 0 to 5 go to bits 0 to 5 on the Teletext chip
//Teletext Latch bit 6 is only passed onto bits 6 on the Teletext chip if DE is true
//Teletext Latch bit 7 goes to LOSE on the Teletext chip
/* Teletext Latch bits 0 to 5 go to bits 0 to 5 on the Teletext chip
Teletext Latch bit 6 is only passed onto bits 6 on the Teletext chip if DE is true
Teletext Latch bit 7 goes to LOSE on the Teletext chip */
if (BIT(ma,13) == 0)
{
m_Teletext_Latch = 0;
}
if (BIT(ma, 13) == 0)
m_teletext_latch = 0;
else
{
m_Teletext_Latch = m_BBC_Video_RAM[calculate_video_address(ma+x_pos,ra)];
}
m_teletext_latch = (m_video_ram[calculate_video_address(ma + x_pos, ra)] & 0x7f) | (m_teletext_latch & 0x80);
m_trom->write((m_Teletext_Latch&0x3f) | (m_Teletext_Latch&0x40));
m_trom->write((m_teletext_latch & 0x3f) | (m_teletext_latch & 0x40) | (de ? 0x00 : 0x40));
m_trom->f1_w(1);
m_trom->f1_w(0);
for(int pixelno=0; pixelno<12; pixelno++)
for (int pixelno = 0; pixelno < 12; pixelno++)
{
m_trom->tr6_w(1);
m_trom->tr6_w(0);
int col=m_trom->get_rgb() ^ ((x_pos==cursor_x) ? 7 : 0);
int col = m_trom->get_rgb() ^ ((x_pos == cursor_x) ? 7 : 0);
int r = BIT(col, 0) * 0xff;
int g = BIT(col, 1) * 0xff;
@ -243,38 +235,24 @@ MC6845_UPDATE_ROW( bbc_state::crtc_update_row )
rgb_t rgb = out_rgb(rgb_t(r, g, b));
bitmap.pix32(y, (x_pos*m_pixels_per_byte) + pixelno) = rgb;
bitmap.pix32(y, (x_pos*m_pixels_per_byte) + pixelno) = de ? rgb : rgb_t::black();
}
}
}
else
{
// this is IC38 and IC41 takes 6845 DisplayEnabled and 6845 RA3
int DE= !(ra>=8);
if (DE)
for (int x_pos = 0; x_pos<x_count; x_pos++)
{
for(int x_pos=0; x_pos<x_count; x_pos++)
{
int vmem = calculate_video_address(ma+x_pos,ra);
unsigned char i = m_BBC_Video_RAM[vmem];
uint8_t i = m_video_ram[calculate_video_address(ma + x_pos, ra)];
for(int pixelno=0; pixelno<m_pixels_per_byte; pixelno++)
{
int col = m_videoULA_palette_lookup[m_pixel_bits[i]] ^ ((x_pos==cursor_x) ? 7 : 0);
bitmap.pix32(y, (x_pos*m_pixels_per_byte)+pixelno) = out_rgb(palette[col]);
i = (i<<1) | 1;
}
}
}
else
{
for(int x_pos=0; x_pos<x_count; x_pos++)
for (int pixelno = 0; pixelno < m_pixels_per_byte; pixelno++)
{
for(int pixelno=0; pixelno<m_pixels_per_byte; pixelno++)
{
bitmap.pix32(y, (x_pos*m_pixels_per_byte)+pixelno) = out_rgb(palette[7]);
}
int col = !(ra & 0x08) ? m_videoULA_palette_lookup[m_pixel_bits[i]] : 7;
col ^= ((cursor_x != -1 && x_pos >= cursor_x && x_pos < (cursor_x + m_cursor_size)) ? 7 : 0);
bitmap.pix32(y, (x_pos*m_pixels_per_byte) + pixelno) = de ? out_rgb(palette[col]) : rgb_t::black();
i = (i << 1) | 1;
}
}
}
@ -282,18 +260,23 @@ MC6845_UPDATE_ROW( bbc_state::crtc_update_row )
WRITE_LINE_MEMBER(bbc_state::bbc_hsync_changed)
{
m_hsync = state ? 1 : 0;
m_hsync = state;
}
WRITE_LINE_MEMBER(bbc_state::bbc_vsync_changed)
{
m_vsync = state ? 1 : 0;
m_vsync = state;
m_trom->dew_w(state);
}
WRITE_LINE_MEMBER(bbc_state::bbc_de_changed)
{
m_display_enable = state ? 1 : 0;
m_video_ula.de = !(BIT(m_hd6845->get_ra(), 3)) && state;
if (!state)
m_teletext_latch |= 0x80;
else
m_teletext_latch &= ~0x80;
}
/**** BBC B+/Master Shadow Ram change ****/
@ -304,9 +287,9 @@ void bbc_state::bbc_setvideoshadow(int vdusel)
// as the video circuitry will already be looking at 0x3000 or so above
// the offset.
if (vdusel)
m_BBC_Video_RAM = m_region_maincpu->base()+0x8000;
m_video_ram = m_region_maincpu->base()+0x8000;
else
m_BBC_Video_RAM = m_region_maincpu->base();
m_video_ram = m_region_maincpu->base();
}
/************************************************************************
@ -316,10 +299,10 @@ void bbc_state::bbc_setvideoshadow(int vdusel)
VIDEO_START_MEMBER(bbc_state, bbc)
{
m_emulation_cursor_size = 1;
m_cursor_size = 1;
set_pixel_lookup();
m_BBC_Video_RAM = m_region_maincpu->base();
m_video_ram = m_region_maincpu->base();
m_memorySize = m_ram->size() / 1024;
}