diff options
Diffstat (limited to 'src/mame/sega/segaic16_road.cpp')
-rw-r--r-- | src/mame/sega/segaic16_road.cpp | 620 |
1 files changed, 620 insertions, 0 deletions
diff --git a/src/mame/sega/segaic16_road.cpp b/src/mame/sega/segaic16_road.cpp new file mode 100644 index 00000000000..9ce28256cce --- /dev/null +++ b/src/mame/sega/segaic16_road.cpp @@ -0,0 +1,620 @@ +// license:BSD-3-Clause +// copyright-holders:Aaron Giles + + +#include "emu.h" +#include "segaic16_road.h" +#include "video/resnet.h" + +DEFINE_DEVICE_TYPE(SEGAIC16_ROAD, segaic16_road_device, "segaic16_road", "Sega 16-bit Road Generator") + +segaic16_road_device::segaic16_road_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) + : device_t(mconfig, SEGAIC16_ROAD, tag, owner, clock) + , m_gfx_region(*this, DEVICE_SELF) + , m_roadram(*this, "roadram") +{ +} + + +void segaic16_road_device::device_start() +{ +} + +void segaic16_road_device::device_reset() +{ +} + + +/******************************************************************************************* + * + * Hang On/Space Harrier-style road chip + * + * Road RAM: + * Offset Bits Usage + * 000-1FF ----pp-- -------- road priority versus tilemaps and sprites + * ------s- -------- (Hang On only) Stripe coloring enable (1=enable) + * ------s- -------- (Space Harrier only) Solid color fill (1=solid, 0=from ROM) + * -------m -------- mirror enable (1=enable) + * -------- iiiiiiii index for other tables + * -------- rrrrrrrr road ROM line select + * 200-3FF ----hhhh hhhhhhhh horizontal scroll + * 400-5FF --bbbbbb -------- background color (colorset 0) + * -------- --bbbbbb background color (colorset 1) + * 600-7FF -------- s------- stripe color index (colorset 1) + * -------- -s------ stripe color index (colorset 0) + * -------- --a----- pixel value 2 color index (colorset 1) + * -------- ---a---- pixel value 2 color index (colorset 0) + * -------- ----b--- pixel value 1 color index (colorset 1) + * -------- -----b-- pixel value 1 color index (colorset 0) + * -------- ------c- pixel value 0 color index (colorset 1) + * -------- -------c pixel value 0 color index (colorset 0) + * + * Logic: + * First, the scanline is used to index into the table at 000-1FF + * + * The index is taken from the low 8 bits of the table value from 000-1FF + * + * The horizontal scroll value is looked up using the index in the table at + * 200-3FF + * + * The background color information is looked up using the index in the table at 400-5FF. + * + * The pixel color information is looked up using the index in the table at 600-7FF. + * + *******************************************************************************************/ + + +void segaic16_road_device::segaic16_road_hangon_decode(road_info *info) +{ + const int len = m_gfx_region.length(); + + /* allocate memory for the unpacked road data */ + info->gfx = std::make_unique<u8[]>(256 * 512); + + /* loop over rows */ + for (int y = 0; y < 256; y++) + { + const u8 *src = m_gfx_region + ((y & 0xff) * 0x40) % len; + u8 *dst = info->gfx.get() + y * 512; + + /* loop over columns */ + for (int x = 0; x < 512; x++) + dst[x] = (((src[x >> 3] >> (~x & 7)) & 1) << 0) | (((src[(x >> 3) + 0x4000] >> (~x & 7)) & 1) << 1); + } +} + + +static void segaic16_road_hangon_draw(segaic16_road_device::road_info *info, bitmap_ind16 &bitmap, const rectangle &cliprect, int priority) +{ + const u16 *roadram = info->roadram; + + /* loop over scanlines */ + for (int y = cliprect.min_y; y <= cliprect.max_y; y++) + { + u16 *const dest = &bitmap.pix(y); + const u16 control = roadram[0x000 + y]; + int hpos = roadram[0x100 + (control & 0xff)]; + const u16 color0 = roadram[0x200 + (control & 0xff)]; + const u16 color1 = roadram[0x300 + (control & 0xff)]; + + /* the PLYCONT signal controls the road layering */ + const u16 plycont = (control >> 10) & 3; + + /* skip layers we aren't supposed to be drawing */ + if ((plycont == 0 && priority != segaic16_road_device::ROAD_BACKGROUND) || + (plycont != 0 && priority != segaic16_road_device::ROAD_FOREGROUND)) + continue; + + /* compute the offset of the road graphics for this line */ + u8 *src = info->gfx.get() + (0x000 + (control & 0xff)) * 512; + + /* initialize the 4-bit counter at 9M, which counts bits within each road byte */ + int ctr9m = hpos & 7; + + /* initialize the two 4-bit counters at 9P (low) and 9N (high), which count road data bytes */ + int ctr9n9p = (hpos >> 3) & 0xff; + + /* initialize the flip-flop at 9J (lower half), which controls the counting direction */ + int ff9j1 = (hpos >> 11) & 1; + + /* initialize the flip-flop at 9J (upper half), which controls the background color */ + int ff9j2 = 1; + + /* initialize the serial shifter at 8S, which delays several signals after we flip */ + int ss8j = 0; + + /* draw this scanline from the beginning */ + for (int x = -24; x <= cliprect.max_x; x++) + { + int color; + + /* ---- the following logic all happens constantly ---- */ + + /* the enable is controlled by the value in the counter at 9M */ + const bool ctr9n9p_ena = (ctr9m == 7); + + /* if we carried out of the 9P/9N counters, we will forcibly clear the flip-flop at 9J (lower half) */ + if ((ctr9n9p & 0xff) == 0xff) + ff9j1 = 0; + + /* if the control word bit 8 is clear, we will forcibly set the flip-flop at 9J (lower half) */ + if (!(control & 0x100)) + ff9j1 = 1; + + /* for the Hang On/Super Hang On case only: if the control word bit 9 is clear, we will forcibly */ + /* set the flip-flip at 9J (upper half) */ + if (info->type == segaic16_road_device::ROAD_HANGON && !(control & 0x200)) + ff9j2 = 1; + + /* ---- now process the pixel ---- */ + int md = 3; + + /* the Space Harrier/Enduro Racer hardware has a tweak that maps the control word bit 9 to the */ + /* /CE line on the road ROM; use this to effectively disable the road data */ + if (info->type != segaic16_road_device::ROAD_SHARRIER || !(control & 0x200)) + + /* the /OE line on the road ROM is linked to the AND of bits 2 & 3 of the counter at 9N */ + if ((ctr9n9p & 0xc0) == 0xc0) + { + /* note that the pixel logic is hidden in a custom at 9S; this is just a guess */ + if (ss8j & 1) + md = src[((ctr9n9p & 0x3f) << 3) | ctr9m]; + else + md = src[((ctr9n9p & 0x3f) << 3) | (ctr9m ^ 7)]; + } + + /* "select" is a made-up signal that comes from bit 3 of the serial shifter and is */ + /* used in several places for color selection */ + int select = (ss8j >> 3) & 1; + + /* check the flip-flop at 9J (upper half) to determine if we should use the background color; */ + /* the output of this is ANDed with M0 and M1 so it only affects pixels with a value of 3; */ + /* this is done by the AND gates at 9L and 7K */ + if (ff9j2 && md == 3) + { + /* in this case, the "select" signal is used to select which background color to use */ + /* since the color0 control word contains two selections */ + color = (color0 >> (select ? 0 : 8)) & 0x3f; + color |= info->colorbase2; + } + + /* if we're not using the background color, we select pixel data from an alternate path */ + else + { + /* the AND gates at 7L, 9K, and 7K clamp the pixel value to 0 if bit 7 of the color 1 */ + /* signal is 1 and if the pixel value is 3 (both M0 and M1 == 1) */ + if ((color1 & 0x80) && md == 3) + md = 0; + + /* the pixel value plus the "select" line combine to form a mux into the low 8 bits of color1 */ + color = (color1 >> ((md << 1) | select)) & 1; + + /* this value becomes the low bit of the final color; the "select" line itself and the pixel */ + /* value form the other bits */ + color |= select << 3; + color |= md << 1; + color |= info->colorbase1; + } + + /* write the pixel if we're past the minimum clip */ + if (x >= cliprect.min_x) + dest[x] = color; + + /* ---- the following logic all happens on the 6M clock ---- */ + + /* clock the counter at 9M */ + ctr9m = (ctr9m + 1) & 7; + + /* if enabled, clock on the two cascaded 4-bit counters at 9P and 9N */ + if (ctr9n9p_ena) + { + if (ff9j1) + ctr9n9p++; + else + ctr9n9p--; + } + + /* clock the flip-flop at 9J (upper half) */ + ff9j2 = !(!ff9j1 && (ss8j & 0x80)); + + /* clock the serial shift register at 8J */ + ss8j = (ss8j << 1) | ff9j1; + } + } +} + + +/******************************************************************************************* + * + * Out Run/X-Board-style road chip + * + * Road control register: + * Bits Usage + * -------- -----d-- (X-board only) Direct scanline mode (1) or indirect mode (0) + * -------- ------pp Road enable/priorities: + * 0 = road 0 only visible + * 1 = both roads visible, road 0 has priority + * 2 = both roads visible, road 1 has priority + * 3 = road 1 only visible + * + * Road RAM: + * Offset Bits Usage + * 000-1FF ----s--- -------- Road 0: Solid fill (1) or ROM fill + * -------- -ccccccc Road 0: Solid color (if solid fill) + * -------i iiiiiiii Road 0: Index for other tables (if in indirect mode) + * -------r rrrrrrr- Road 0: Road ROM line select + * 200-3FF ----s--- -------- Road 1: Solid fill (1) or ROM fill + * -------- -ccccccc Road 1: Solid color (if solid fill) + * -------i iiiiiiii Road 1: Index for other tables (if in indirect mode) + * -------r rrrrrrr- Road 1: Road ROM line select + * 400-7FF ----hhhh hhhhhhhh Road 0: horizontal scroll + * 800-BFF ----hhhh hhhhhhhh Road 1: horizontal scroll + * C00-FFF ----bbbb -------- Background color index + * -------- s------- Road 1: stripe color index + * -------- -a------ Road 1: pixel value 2 color index + * -------- --b----- Road 1: pixel value 1 color index + * -------- ---c---- Road 1: pixel value 0 color index + * -------- ----s--- Road 0: stripe color index + * -------- -----a-- Road 0: pixel value 2 color index + * -------- ------b- Road 0: pixel value 1 color index + * -------- -------c Road 0: pixel value 0 color index + * + * Logic: + * First, the scanline is used to index into the tables at 000-1FF/200-3FF + * - if solid fill, the background is filled with the specified color index + * - otherwise, the remaining tables are used + * + * If indirect mode is selected, the index is taken from the low 9 bits of the + * table value from 000-1FF/200-3FF + * If direct scanline mode is selected, the index is set equal to the scanline + * for road 0, or the scanline + 256 for road 1 + * + * The horizontal scroll value is looked up using the index in the tables at + * 400-7FF/800-BFF + * + * The color information is looked up using the index in the table at C00-FFF. Note + * that the same table is used for both roads. + * + * + * Out Run road priorities are controlled by a PAL that maps as indicated below. + * This was used to generate the priority_map. It is assumed that X-board is the + * same, though this logic is locked inside a Sega custom. + * + * RRC0 = CENTA & (RDA == 3) & !RRC2 + * | CENTB & (RDB == 3) & RRC2 + * | (RDA == 1) & !RRC2 + * | (RDB == 1) & RRC2 + * + * RRC1 = CENTA & (RDA == 3) & !RRC2 + * | CENTB & (RDB == 3) & RRC2 + * | (RDA == 2) & !RRC2 + * | (RDB == 2) & RRC2 + * + * RRC2 = !/HSYNC & IIQ + * | (CTRL == 3) + * | !CENTA & (RDA == 3) & !CENTB & (RDB == 3) & (CTRL == 2) + * | CENTB & (RDB == 3) & (CTRL == 2) + * | !CENTA & (RDA == 3) & !M2 & (CTRL == 2) + * | !CENTA & (RDA == 3) & !M3 & (CTRL == 2) + * | !M0 & (RDB == 0) & (CTRL == 2) + * | !M1 & (RDB == 0) & (CTRL == 2) + * | !CENTA & (RDA == 3) & CENTB & (RDB == 3) & (CTRL == 1) + * | !M0 & CENTB & (RDB == 3) & (CTRL == 1) + * | !M1 & CENTB & (RDB == 3) & (CTRL == 1) + * | !CENTA & M0 & (RDB == 0) & (CTRL == 1) + * | !CENTA & M1 & (RDB == 0) & (CTRL == 1) + * | !CENTA & (RDA == 3) & (RDB == 1) & (CTRL == 1) + * | !CENTA & (RDA == 3) & (RDB == 2) & (CTRL == 1) + * + * RRC3 = VA11 & VB11 + * | VA11 & (CTRL == 0) + * | (CTRL == 3) & VB11 + * + * RRC4 = !CENTA & (RDA == 3) & !CENTB & (RDB == 3) + * | VA11 & VB11 + * | VA11 & (CTRL == 0) + * | (CTRL == 3) & VB11 + * | !CENTB & (RDB == 3) & (CTRL == 3) + * | !CENTA & (RDA == 3) & (CTRL == 0) + * + *******************************************************************************************/ + +void segaic16_road_device::segaic16_road_outrun_decode(road_info *info) +{ + const int len = m_gfx_region.length(); + + /* allocate memory for the unpacked road data */ + info->gfx = std::make_unique<u8[]>((256 * 2 + 1) * 512); + + /* loop over rows */ + for (int y = 0; y < 256 * 2; y++) + { + const u8 *src = m_gfx_region + ((y & 0xff) * 0x40 + (y >> 8) * 0x8000) % len; + u8 *dst = info->gfx.get() + y * 512; + + /* loop over columns */ + for (int x = 0; x < 512; x++) + { + dst[x] = (((src[x >> 3] >> (~x & 7)) & 1) << 0) | (((src[(x >> 3) + 0x4000] >> (~x & 7)) & 1) << 1); + + /* pre-mark road data in the "stripe" area with a high bit */ + if (x >= 256-8 && x < 256 && dst[x] == 3) + dst[x] |= 4; + } + } + + /* set up a dummy road in the last entry */ + memset(info->gfx.get() + 256 * 2 * 512, 3, 512); +} + + +static void segaic16_road_outrun_draw(segaic16_road_device::road_info *info, bitmap_ind16 &bitmap, const rectangle &cliprect, int priority) +{ + const u16 *roadram = info->buffer.get(); + + /* loop over scanlines */ + for (int y = cliprect.min_y; y <= cliprect.max_y; y++) + { + static const u8 priority_map[2][8] = + { + { 0x80,0x81,0x81,0x87,0,0,0,0x00 }, + { 0x81,0x81,0x81,0x8f,0,0,0,0x80 } +// +// Original guesses from X-board priorities: +// { 0x80,0x81,0x81,0x83,0,0,0,0x00 }, +// { 0x81,0x87,0x87,0x8f,0,0,0,0x00 } + }; + u16 *const dest = &bitmap.pix(y); + const u16 data0 = roadram[0x000 + y]; + const u16 data1 = roadram[0x100 + y]; + + /* background case: look for solid fill scanlines */ + if (priority == segaic16_road_device::ROAD_BACKGROUND) + { + int color = -1; + + /* based on the info->control, we can figure out which sky to draw */ + switch (info->control & 3) + { + case 0: + if (data0 & 0x800) + color = data0 & 0x7f; + break; + + case 1: + if (data0 & 0x800) + color = data0 & 0x7f; + else if (data1 & 0x800) + color = data1 & 0x7f; + break; + + case 2: + if (data1 & 0x800) + color = data1 & 0x7f; + else if (data0 & 0x800) + color = data0 & 0x7f; + break; + + case 3: + if (data1 & 0x800) + color = data1 & 0x7f; + break; + } + + /* fill the scanline with color */ + if (color != -1) + { + color |= info->colorbase3; + for (int x = cliprect.min_x; x <= cliprect.max_x; x++) + dest[x] = color; + } + } + + /* foreground case: render from ROM */ + else + { + const u8 control = info->control & 3; + u16 color_table[32]; + + /* if both roads are low priority, skip */ + if ((data0 & 0x800) && (data1 & 0x800)) + continue; + + /* get road 0 data */ + u8 *src0 = (data0 & 0x800) ? info->gfx.get() + 256 * 2 * 512 : (info->gfx.get() + (0x000 + ((data0 >> 1) & 0xff)) * 512); + int hpos0 = (roadram[0x200 + ((info->control & 4) ? y : (data0 & 0x1ff))]) & 0xfff; + int color0 = roadram[0x600 + ((info->control & 4) ? y : (data0 & 0x1ff))]; + + /* get road 1 data */ + u8 *src1 = (data1 & 0x800) ? info->gfx.get() + 256 * 2 * 512 : (info->gfx.get() + (0x100 + ((data1 >> 1) & 0xff)) * 512); + int hpos1 = (roadram[0x400 + ((info->control & 4) ? (0x100 + y) : (data1 & 0x1ff))]) & 0xfff; + int color1 = roadram[0x600 + ((info->control & 4) ? (0x100 + y) : (data1 & 0x1ff))]; + + /* determine the 5 colors for road 0 */ + color_table[0x00] = info->colorbase1 ^ 0x00 ^ ((color0 >> 0) & 1); + color_table[0x01] = info->colorbase1 ^ 0x02 ^ ((color0 >> 1) & 1); + color_table[0x02] = info->colorbase1 ^ 0x04 ^ ((color0 >> 2) & 1); + u8 bgcolor = (color0 >> 8) & 0xf; + color_table[0x03] = (data0 & 0x200) ? color_table[0x00] : (info->colorbase2 ^ 0x00 ^ bgcolor); + color_table[0x07] = info->colorbase1 ^ 0x06 ^ ((color0 >> 3) & 1); + + /* determine the 5 colors for road 1 */ + color_table[0x10] = info->colorbase1 ^ 0x08 ^ ((color1 >> 4) & 1); + color_table[0x11] = info->colorbase1 ^ 0x0a ^ ((color1 >> 5) & 1); + color_table[0x12] = info->colorbase1 ^ 0x0c ^ ((color1 >> 6) & 1); + bgcolor = (color1 >> 8) & 0xf; + color_table[0x13] = (data1 & 0x200) ? color_table[0x10] : (info->colorbase2 ^ 0x10 ^ bgcolor); + color_table[0x17] = info->colorbase1 ^ 0x0e ^ ((color1 >> 7) & 1); + + /* draw the road */ + switch (control) + { + case 0: + if (data0 & 0x800) + continue; + hpos0 = (hpos0 - (0x5f8 + info->xoffs)) & 0xfff; + for (int x = cliprect.min_x; x <= cliprect.max_x; x++) + { + const int pix0 = (hpos0 < 0x200) ? src0[hpos0] : 3; + dest[x] = color_table[0x00 + pix0]; + hpos0 = (hpos0 + 1) & 0xfff; + } + break; + + case 1: + hpos0 = (hpos0 - (0x5f8 + info->xoffs)) & 0xfff; + hpos1 = (hpos1 - (0x5f8 + info->xoffs)) & 0xfff; + for (int x = cliprect.min_x; x <= cliprect.max_x; x++) + { + const int pix0 = (hpos0 < 0x200) ? src0[hpos0] : 3; + const int pix1 = (hpos1 < 0x200) ? src1[hpos1] : 3; + if ((priority_map[0][pix0] >> pix1) & 1) + dest[x] = color_table[0x10 + pix1]; + else + dest[x] = color_table[0x00 + pix0]; + hpos0 = (hpos0 + 1) & 0xfff; + hpos1 = (hpos1 + 1) & 0xfff; + } + break; + + case 2: + hpos0 = (hpos0 - (0x5f8 + info->xoffs)) & 0xfff; + hpos1 = (hpos1 - (0x5f8 + info->xoffs)) & 0xfff; + for (int x = cliprect.min_x; x <= cliprect.max_x; x++) + { + const int pix0 = (hpos0 < 0x200) ? src0[hpos0] : 3; + const int pix1 = (hpos1 < 0x200) ? src1[hpos1] : 3; + if ((priority_map[1][pix0] >> pix1) & 1) + dest[x] = color_table[0x10 + pix1]; + else + dest[x] = color_table[0x00 + pix0]; + hpos0 = (hpos0 + 1) & 0xfff; + hpos1 = (hpos1 + 1) & 0xfff; + } + break; + + case 3: + if (data1 & 0x800) + continue; + hpos1 = (hpos1 - (0x5f8 + info->xoffs)) & 0xfff; + for (int x = cliprect.min_x; x <= cliprect.max_x; x++) + { + const int pix1 = (hpos1 < 0x200) ? src1[hpos1] : 3; + dest[x] = color_table[0x10 + pix1]; + hpos1 = (hpos1 + 1) & 0xfff; + } + break; + } + } + } +} + + + +/************************************* + * + * General road initialization + * + *************************************/ + +void segaic16_road_device::segaic16_road_init(int which, int type, int colorbase1, int colorbase2, int colorbase3, int xoffs) +{ + road_info *info = &segaic16_road[which]; + + /* reset the tilemap info */ + *info = road_info(); + info->index = which; + info->type = type; + info->colorbase1 = colorbase1; + info->colorbase2 = colorbase2; + info->colorbase3 = colorbase3; + info->xoffs = xoffs; + + /* set up based on which road generator */ + switch (which) + { + case 0: + info->roadram = m_roadram.target(); + break; + + default: + fatalerror("Invalid road index specified in segaic16_road_init\n"); + } + + /* determine the parameters of the road */ + switch (type) + { + case ROAD_HANGON: + case ROAD_SHARRIER: + info->draw = segaic16_road_hangon_draw; + segaic16_road_hangon_decode(info); + break; + + case ROAD_OUTRUN: + case ROAD_XBOARD: + info->buffer = std::make_unique<u16[]>(0x1000/2); + info->draw = segaic16_road_outrun_draw; + segaic16_road_outrun_decode(info); + break; + + default: + fatalerror("Invalid road system specified in segaic16_road_init\n"); + } +} + + + +/************************************* + * + * General road drawing + * + *************************************/ + +void segaic16_road_device::segaic16_road_draw(int which, bitmap_ind16 &bitmap, const rectangle &cliprect, int priority) +{ + road_info *info = &segaic16_road[which]; + (*info->draw)(info, bitmap, cliprect, priority); +} + + + +/************************************* + * + * General road control read/write + * + *************************************/ + +u16 segaic16_road_device::segaic16_road_control_0_r() +{ + if (!machine().side_effects_disabled()) + { + road_info *info = &segaic16_road[0]; + + if (info->buffer) + { + u32 *src = (u32 *)info->roadram; + u32 *dst = (u32 *)info->buffer.get(); + + /* swap the halves of the road RAM */ + for (int i = 0; i < 0x1000/4; i++) + { + const u32 temp = *src; + *src++ = *dst; + *dst++ = temp; + } + } + } + + return 0xffff; +} + + +void segaic16_road_device::segaic16_road_control_0_w(offs_t offset, u16 data, u16 mem_mask) +{ + road_info *info = &segaic16_road[0]; + + if (ACCESSING_BITS_0_7) + { + info->control = data & ((info->type == ROAD_OUTRUN) ? 3 : 7); + } +} |