// license:BSD-3-Clause // copyright-holders:Mike Balfour, Aaron Giles /*************************************************************************** Atari Cloud 9 (prototype) hardware ***************************************************************************/ #include "emu.h" #include "includes/cloud9.h" #include "video/resnet.h" /************************************* * * Video startup * *************************************/ void cloud9_state::video_start() { static const int resistances[3] = { 22000, 10000, 4700 }; /* allocate second bank of videoram */ m_videoram = std::make_unique(0x8000); membank("bank1")->set_base(m_videoram.get()); /* get pointers to our PROMs */ m_syncprom = memregion("proms")->base() + 0x000; m_wpprom = memregion("proms")->base() + 0x200; m_priprom = memregion("proms")->base() + 0x300; /* compute the color output resistor weights at startup */ compute_resistor_weights(0, 255, -1.0, 3, resistances, m_rweights, 1000, 0, 3, resistances, m_gweights, 1000, 0, 3, resistances, m_bweights, 1000, 0); /* allocate a bitmap for drawing sprites */ m_screen->register_screen_bitmap(m_spritebitmap); /* register for savestates */ save_pointer(NAME(m_videoram), 0x8000); save_item(NAME(m_bitmode_addr)); } /************************************* * * Palette RAM accesses * *************************************/ WRITE8_MEMBER(cloud9_state::cloud9_paletteram_w) { int bit0, bit1, bit2; int r, g, b; /* extract the raw RGB bits */ r = (data & 0xe0) >> 5; g = (data & 0x1c) >> 2; b = ((data & 0x03) << 1) | ((offset & 0x40) >> 6); /* red component (inverted) */ bit0 = (~r >> 0) & 0x01; bit1 = (~r >> 1) & 0x01; bit2 = (~r >> 2) & 0x01; r = combine_3_weights(m_rweights, bit0, bit1, bit2); /* green component (inverted) */ bit0 = (~g >> 0) & 0x01; bit1 = (~g >> 1) & 0x01; bit2 = (~g >> 2) & 0x01; g = combine_3_weights(m_gweights, bit0, bit1, bit2); /* blue component (inverted) */ bit0 = (~b >> 0) & 0x01; bit1 = (~b >> 1) & 0x01; bit2 = (~b >> 2) & 0x01; b = combine_3_weights(m_bweights, bit0, bit1, bit2); m_palette->set_pen_color(offset & 0x3f, rgb_t(r, g, b)); } /************************************* * * Video RAM access via the write * protect PROM * *************************************/ inline void cloud9_state::cloud9_write_vram( uint16_t addr, uint8_t data, uint8_t bitmd, uint8_t pixba ) { uint8_t *dest = &m_videoram[0x0000 | (addr & 0x3fff)]; uint8_t *dest2 = &m_videoram[0x4000 | (addr & 0x3fff)]; uint8_t promaddr = 0; uint8_t wpbits; /* Inputs to the write-protect PROM: Bit 7 = BITMD Bit 6 = video_control[4] Bit 5 = video_control[6] Bit 4 = 1 if (A15-A12 != 4) Bit 3 = !(A13 | A12 | A11) Bit 2 = A9 & A10 Bit 1 = PIXB Bit 0 = PIXA */ promaddr |= bitmd << 7; promaddr |= m_videolatch->q4_r() << 6; promaddr |= m_videolatch->q6_r() << 5; promaddr |= ((addr & 0xf000) != 0x4000) << 4; promaddr |= ((addr & 0x3800) == 0x0000) << 3; promaddr |= ((addr & 0x0600) == 0x0600) << 2; promaddr |= (pixba << 0); /* look up the PROM result */ wpbits = m_wpprom[promaddr]; /* write to the appropriate parts of VRAM depending on the result */ if (!(wpbits & 1)) dest2[0] = (dest2[0] & 0x0f) | (data & 0xf0); if (!(wpbits & 2)) dest2[0] = (dest2[0] & 0xf0) | (data & 0x0f); if (!(wpbits & 4)) dest[0] = (dest[0] & 0x0f) | (data & 0xf0); if (!(wpbits & 8)) dest[0] = (dest[0] & 0xf0) | (data & 0x0f); } /************************************* * * Autoincrement control for bit mode * *************************************/ inline void cloud9_state::bitmode_autoinc( ) { /* auto increment in the x-direction if it's enabled */ if (!m_videolatch->q0_r()) /* /AX */ m_bitmode_addr[0]++; /* auto increment in the y-direction if it's enabled */ if (!m_videolatch->q1_r()) /* /AY */ m_bitmode_addr[1]++; } /************************************* * * Standard video RAM access * *************************************/ WRITE8_MEMBER(cloud9_state::cloud9_videoram_w) { /* direct writes to VRAM go through the write protect PROM as well */ cloud9_write_vram(offset, data, 0, 0); } /************************************* * * Bit mode video RAM access * *************************************/ READ8_MEMBER(cloud9_state::cloud9_bitmode_r) { /* in bitmode, the address comes from the autoincrement latches */ uint16_t addr = (m_bitmode_addr[1] << 6) | (m_bitmode_addr[0] >> 2); /* the appropriate pixel is selected into the upper 4 bits */ uint8_t result = m_videoram[((~m_bitmode_addr[0] & 2) << 13) | addr] << ((m_bitmode_addr[0] & 1) * 4); /* autoincrement because /BITMD was selected */ bitmode_autoinc(); /* the upper 4 bits of the data lines are not driven so make them all 1's */ return (result >> 4) | 0xf0; } WRITE8_MEMBER(cloud9_state::cloud9_bitmode_w) { /* in bitmode, the address comes from the autoincrement latches */ uint16_t addr = (m_bitmode_addr[1] << 6) | (m_bitmode_addr[0] >> 2); /* the lower 4 bits of data are replicated to the upper 4 bits */ data = (data & 0x0f) | (data << 4); /* write through the generic VRAM routine, passing the low 2 X bits as PIXB/PIXA */ cloud9_write_vram(addr, data, 1, m_bitmode_addr[0] & 3); /* autoincrement because /BITMD was selected */ bitmode_autoinc(); } WRITE8_MEMBER(cloud9_state::cloud9_bitmode_addr_w) { /* write through to video RAM and also to the addressing latches */ cloud9_write_vram(offset, data, 0, 0); m_bitmode_addr[offset] = data; } /************************************* * * Video updating * *************************************/ uint32_t cloud9_state::screen_update_cloud9(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect) { uint8_t *spriteaddr = m_spriteram; int flip = m_videolatch->q5_r() ? 0xff : 0x00; /* PLAYER2 */ pen_t black = m_palette->black_pen(); int x, y, offs; /* draw the sprites */ m_spritebitmap.fill(0x00, cliprect); for (offs = 0; offs < 0x20; offs++) if (spriteaddr[offs + 0x00] != 0) { int x = spriteaddr[offs + 0x60]; int y = 256 - 15 - spriteaddr[offs + 0x00]; int xflip = spriteaddr[offs + 0x40] & 0x80; int yflip = spriteaddr[offs + 0x40] & 0x40; int which = spriteaddr[offs + 0x20]; int color = 0; m_gfxdecode->gfx(0)->transpen(m_spritebitmap,cliprect, which, color, xflip, yflip, x, y, 0); if (x >= 256 - 16) m_gfxdecode->gfx(0)->transpen(m_spritebitmap,cliprect, which, color, xflip, yflip, x - 256, y, 0); } /* draw the bitmap to the screen, looping over Y */ for (y = cliprect.min_y; y <= cliprect.max_y; y++) { uint16_t *dst = &bitmap.pix16(y); /* if we're in the VBLANK region, just fill with black */ if (~m_syncprom[y] & 2) { for (x = cliprect.min_x; x <= cliprect.max_x; x++) dst[x] = black; } /* non-VBLANK region: merge the sprites and the bitmap */ else { uint16_t *mosrc = &m_spritebitmap.pix16(y); int effy = y ^ flip; uint8_t *src[2]; /* two videoram arrays */ src[0] = &m_videoram[0x4000 | (effy * 64)]; src[1] = &m_videoram[0x0000 | (effy * 64)]; /* loop over X */ for (x = cliprect.min_x; x <= cliprect.max_x; x++) { /* if we're in the HBLANK region, just store black */ if (x >= 256) dst[x] = black; /* otherwise, process normally */ else { int effx = x ^ flip; /* low 4 bits = left pixel, high 4 bits = right pixel */ uint8_t pix = (src[(effx >> 1) & 1][effx / 4] >> ((~effx & 1) * 4)) & 0x0f; uint8_t mopix = mosrc[x]; /* sprites have priority if sprite pixel != 0 or some other condition */ if (mopix != 0) pix = mopix | 0x10; /* the high bit is the bank select */ pix |= m_videolatch->q7_r() << 5; /* store the pixel value and also a priority value based on the topmost bit */ dst[x] = pix; } } } } return 0; }