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Diffstat (limited to 'src/mame/video/rmnimbus.c')
-rw-r--r-- | src/mame/video/rmnimbus.c | 514 |
1 files changed, 514 insertions, 0 deletions
diff --git a/src/mame/video/rmnimbus.c b/src/mame/video/rmnimbus.c new file mode 100644 index 00000000000..4ef72cac7c0 --- /dev/null +++ b/src/mame/video/rmnimbus.c @@ -0,0 +1,514 @@ +// license:BSD-3-Clause +// copyright-holders:Phill Harvey-Smith, Carl +/* + video/rmnimbus.c + + Research machines Nimbus. + + 2009-11-14, P.Harvey-Smith. + + This is my best guess implementation of the operation of the Nimbus + video system. + + On the real machine, the Video chip has a block of 64K of memory which is + completely separate from the main 80186 memory. + + The main CPU write to the video chip via a series of registers in the + 0x0000 to 0x002F reigon, the video chip then manages all video memory + from there. + + As I cannot find a datasheet for the vide chip marked + MB61H201 Fujitsu RML 12835 GCV, I have had to determine most of its + operation by disassembling the Nimbus bios and by writing experemental + code on the real machine. +*/ + +#include "emu.h" +#include "debug/debugcpu.h" +#include "debug/debugcon.h" +#include "includes/rmnimbus.h" + + +#define WIDTH_MASK 0x07 + +#define FG_COLOUR (m_colours&0x0F) +#define BG_COLOUR ((m_colours&0xF0)>>4) +#define SELECT_COL(x,c) (IS_80COL ? ((((x) & 1) ? ((c) << 2) : (c)) & 0xC) : (c)) +#define FILL_WORD(c) (((c) << 12) | ((c) << 8) | ((c) << 4) | (c)) + +#define IS_80COL (m_mode&0x10) +#define IS_XOR (m_op&8) + +#define DEBUG_TEXT 0x01 +#define DEBUG_DB 0x02 +#define DEBUG_PIXEL 0x04 + +#define DEBUG_SET(flags) ((m_debug_video & (flags))==(flags)) + +static void video_debug(running_machine &machine, int ref, int params, const char *param[]); + +READ16_MEMBER(rmnimbus_state::nimbus_video_io_r) +{ + UINT16 result = 0; + + switch (offset) + { + case 0x00: + case 0x08: + result = read_pixel_data(m_x, m_y); + break; + case 0x02: + case 0x0A: + result = read_pixel_data(m_x, ++m_y); + break; + case 0x05: + case 0x0D: + result = read_pixel_data(++m_x, m_y); + break; + + case 0x10: + result = m_yline; + break; + case 0x11: + result = m_op; + break; + case 0x12: + result = m_colours; + break; + case 0x13: + result = m_mode; + break; + case 0x14: + result = m_screen->vpos() % 0xb; // TODO: verify + break; + case 0x15: + result = m_x; + break; + case 0x16: + result = m_y; + break; + default: + logerror("nimbus: unknown video reg read %02x\n", offset); + break; + } + + if(DEBUG_SET(DEBUG_TEXT)) + logerror("Nimbus video IOR at %05X from %04X mask=%04X, data=%04X\n",space.device().safe_pc(),(offset*2),mem_mask,result); + + return result; +} + +UINT8 rmnimbus_state::get_pixel(UINT16 x, UINT16 y) +{ + UINT8 result = 0; + + if((x<640) && (y<250)) + { + if(IS_80COL) + result=m_video_mem.pix16(y, x) >> 2; + else + result=m_video_mem.pix16(y, x*2); + } + + return result; +} + +UINT16 rmnimbus_state::read_pixel_line(UINT16 x, UINT16 y, UINT8 pixels, UINT8 bpp) +{ + UINT16 colour = 0; + int i; + x *= pixels; + + if(DEBUG_SET(DEBUG_TEXT | DEBUG_PIXEL)) + logerror("read_pixel_line(x=%d, y=%d, width=%d, bpp=%d)\n",x,y,pixels,bpp); + + for(i = 0; i < pixels - 1; i++) + { + colour |= get_pixel(i + x, y); + + if(bpp==1) + colour=((colour==SELECT_COL(x + i, FG_COLOUR)) ? 1 : 0) << 1; + else + colour <<= bpp; + } + return colour | get_pixel(x + i, y); +} + +UINT16 rmnimbus_state::read_pixel_data(UINT16 x, UINT16 y) +{ + UINT16 result=0; + + if(DEBUG_SET(DEBUG_TEXT | DEBUG_PIXEL)) + logerror("read_pixel_data(x=%d, y=%d), reg022=%04X\n",x,y,m_op); + + if(IS_80COL) + { + switch (m_op & WIDTH_MASK) + { + case 0x00 : break; + + case 0x01 : break; + + case 0x02 : break; + + case 0x03 : break; + + case 0x04 : + result=read_pixel_line(x,y,4,2); + break; + + case 0x05 : break; + + case 0x06 : + result=read_pixel_line(x,y,8,2); + break; + + case 0x07 : break; + } + } + else /* 40 Col */ + { + switch (m_op & WIDTH_MASK) + { + case 0x00 : break; + + case 0x01 : break; + + case 0x02 : break; + + case 0x03 : break; + + case 0x04 : break; + + case 0x05 : break; + + case 0x06 : + result=read_pixel_line(x,y,4,4); + break; + + case 0x07 : break; + } + } + + return result; +} + +/* + Write to the video registers. + + Incase anyone wonders about the DEBUG_DB statement, this allows me to log which registers + are being written to and then play them back at the real machine, this has helped greatly + in figuring out what the video registers do. + +*/ + +WRITE16_MEMBER(rmnimbus_state::nimbus_video_io_w) +{ + UINT16 colours = data; + if(offset < 0x14) + { + if(DEBUG_SET(DEBUG_TEXT)) + logerror("Nimbus video IOW at %05X write of %04X to %04X mask=%04X\n",space.device().safe_pc(),data,(offset*2),mem_mask); + + if(DEBUG_SET(DEBUG_DB)) + logerror("dw %05X,%05X\n",(offset*2),data); + } + + switch (offset) + { + case 0x00: + case 0x08: + break; + + case 0x09: + colours = FILL_WORD(FG_COLOUR); + case 0x01: + m_x = data; + break; + + case 0x02: + case 0x0A: + m_y++; + break; + + case 0x0B: + colours = FILL_WORD(FG_COLOUR); + case 0x03: + m_x = data; + m_y++; + break; + + case 0x05: + case 0x0D: + m_x++; + break; + + case 0x0E: + colours = FILL_WORD(FG_COLOUR); + case 0x06: + m_y = data; + break; + + case 0x0F: + colours = FILL_WORD(FG_COLOUR); + case 0x07: + m_y = data; + m_x++; + break; + + case 0x10: + m_yline = data; + return; + case 0x11: + m_op = data; + return; + case 0x12: + m_colours = data; + return; + case 0x13: + /* + bits 0..3 of reg026 contain the border colour. + bit 5 contains the 40/80 column (320/640 pixel) flag. + */ + m_mode = data; + return; + case 0x14: + case 0x15: + case 0x16: + case 0x17: + change_palette(offset - 0x14, data); + return; + + default: + logerror("nimbus: unknown video reg write %02x %04x\n", offset, data); + return; + } + if(offset & 0x08) + write_pixel_data(m_x, m_y, colours); +} + +void rmnimbus_state::set_pixel(UINT16 x, UINT16 y, UINT8 colour) +{ + if(DEBUG_SET(DEBUG_TEXT | DEBUG_PIXEL)) + logerror("set_pixel(x=%d, y=%d, colour=%04X), IS_XOR=%02X\n",x,y,colour,IS_XOR); + + if((x<640) && (y<250)) + { + if(IS_XOR) + m_video_mem.pix16(y, x)^=colour; + else + m_video_mem.pix16(y, x)=colour; + } +} + +void rmnimbus_state::set_pixel40( UINT16 x, UINT16 y, UINT8 colour) +{ + set_pixel((x*2),y,colour); + set_pixel((x*2)+1,y,colour); +} + +void rmnimbus_state::write_pixel_line(UINT16 x, UINT16 y, UINT16 data, UINT8 pixels, UINT8 bpp) +{ + UINT8 colour; + UINT8 mask = (1 << bpp) - 1; + x *= pixels; + + if(DEBUG_SET(DEBUG_TEXT | DEBUG_PIXEL)) + logerror("write_pixel_line(x=%d, y=%d, data=%04X, width=%d, bpp=%d)\n",x,y,data,pixels,bpp); + + for(int i = (pixels - 1); i >= 0; i--) + { + if(bpp==1) + colour = SELECT_COL(x + i, (data & 1) ? FG_COLOUR : BG_COLOUR); + else if(IS_80COL) + colour = (data & mask) << 2; + else + colour = (data & mask); + + if(IS_80COL) + set_pixel(x + i,y,colour); + else + set_pixel40(x + i,y,colour); + + data >>= bpp; + } +} + +void rmnimbus_state::move_pixel_line(UINT16 x, UINT16 y, UINT8 pixels) +{ + x *= pixels; + if(DEBUG_SET(DEBUG_TEXT | DEBUG_PIXEL)) + logerror("move_pixel_line(x=%d, y=%d, width=%d)\n",x,y,pixels); + + for(int i = 0; i < pixels; i++) + { + if(DEBUG_SET(DEBUG_TEXT | DEBUG_PIXEL)) + logerror("x=%d\n",x + i); + m_video_mem.pix16(m_yline, x + i) = m_video_mem.pix16(y, x + i); + } +} + + + +/* + The values in the bottom 3 bits of reg022 seem to determine the number of bits per pixel + for following operations. + + The values that I have decoded so far are : + + 000 1bpp, foreground and background colours taken from reg024 + 001 2bpp, using the first 4 colours of the pallette + 010 + 011 + 100 4bpp, must be a 16 bit word, of which the upper byte is a mask anded with existing pixels then ored + with the lower byte containing the pixel data for two pixels. + 101 Move pixel data at x,reg020 to x,y, used for scrolling. + 110 if 40 col + 4bpp, 16 bit word containing the pixel data for 4 pixels. + else + 2bpp, 16 bit word containing the pixel data for 8 pixels. + 111 + + Bit 3 of reg022 is as follows : + + 0 pixels are written from supplied colour data + 1 pixels are xor'ed onto the screen +*/ + +void rmnimbus_state::write_pixel_data(UINT16 x, UINT16 y, UINT16 data) +{ + if(DEBUG_SET(DEBUG_TEXT | DEBUG_PIXEL)) + logerror("write_pixel_data(x=%d, y=%d, data=%04X), reg022=%04X\n",x,y,data,m_op); + + if(IS_80COL) + { + switch (m_op & WIDTH_MASK) + { + case 0x00: + write_pixel_line(x,y,data,16,1); + break; + + case 0x01: + write_pixel_line(x,y,data,8,1); + break; + + case 0x02: + write_pixel_line(x,y,data,8,1); + break; + + case 0x03: + set_pixel(x,y,SELECT_COL(x, FG_COLOUR)); + break; + + case 0x04: + write_pixel_line(x,y,(((data & 0xFF00)>>8) & (data & 0xFF)) | (~((data & 0xFF00)>>8) & read_pixel_line(x,y,4,2)),4,2); + break; + + case 0x05: + move_pixel_line(x,y,16); + break; + + case 0x06: + write_pixel_line(x,y,data,8,2); + break; + + case 0x07: + set_pixel(x,y,SELECT_COL(x, FG_COLOUR)); + break; + } + } + else /* 40 Col */ + { + switch (m_op & WIDTH_MASK) + { + case 0x00: + write_pixel_line(x,y,data,8,1); + break; + + case 0x01: + write_pixel_line(x,y,data,4,2); + break; + + case 0x02: + set_pixel40(x,y,FG_COLOUR); + break; + + case 0x03: + set_pixel(x,y,FG_COLOUR); + break; + + case 0x04: + write_pixel_line(x,y,(((data & 0xFF00)>>8) & (data & 0xFF)) | (~((data & 0xFF00)>>8) & read_pixel_line(x,y,2,4)),2,4); + break; + + case 0x05: + move_pixel_line(x,y,16); + break; + + case 0x06: + write_pixel_line(x,y,data,4,4); + break; + + case 0x07: + set_pixel(x,y,FG_COLOUR); + break; + } + } +} + +void rmnimbus_state::change_palette(UINT8 bank, UINT16 colours) +{ + // loop over changing colours + for(int colourno = (bank * 4); colourno < ((bank + 1) * 4); colourno++) + { + int i = (colours & 8) >> 3; + m_palette->set_pen_color(colourno, pal2bit((colours & 2) | i), pal2bit(((colours & 4) >> 1) | i), pal2bit(((colours & 1) << 1) | i)); + + if(DEBUG_SET(DEBUG_TEXT)) + logerror("set colourno[%02X], colour=%02X\n",colourno, colours & 0xf); + colours >>= 4; + } +} + +static void video_debug(running_machine &machine, int ref, int params, const char *param[]) +{ + rmnimbus_state *state = machine.driver_data<rmnimbus_state>(); + if(params>0) + { + int temp; + sscanf(param[0],"%d",&temp); state->m_debug_video = temp; + } + else + { + debug_console_printf(machine,"Error usage : nimbus_vid_debug <debuglevel>\n"); + debug_console_printf(machine,"Current debuglevel=%02X\n",state->m_debug_video); + } +} + +void rmnimbus_state::video_start() +{ + m_debug_video=0; + + m_screen->register_screen_bitmap(m_video_mem); + + if (machine().debug_flags & DEBUG_FLAG_ENABLED) + { + debug_console_register_command(machine(), "nimbus_vid_debug", CMDFLAG_NONE, 0, 0, 1, video_debug); + } +} + +void rmnimbus_state::video_reset() +{ + m_mode = 0; + m_x = 0; + m_y = 0; + m_op = 0; + m_yline = 0; +} + +UINT32 rmnimbus_state::screen_update_nimbus(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) +{ + copybitmap(bitmap, m_video_mem, 0, 0, 0, 0, cliprect); + + return 0; +} |