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dsp4emu.c
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/**********************************************************************************
Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
(c) Copyright 1996 - 2002 Gary Henderson ([email protected]),
Jerremy Koot ([email protected])
(c) Copyright 2002 - 2004 Matthew Kendora
(c) Copyright 2002 - 2005 Peter Bortas ([email protected])
(c) Copyright 2004 - 2005 Joel Yliluoma (http://iki.fi/bisqwit/)
(c) Copyright 2001 - 2006 John Weidman ([email protected])
(c) Copyright 2002 - 2006 funkyass ([email protected]),
Kris Bleakley ([email protected])
(c) Copyright 2002 - 2007 Brad Jorsch ([email protected]),
Nach ([email protected]),
zones ([email protected])
(c) Copyright 2006 - 2007 nitsuja
BS-X C emulator code
(c) Copyright 2005 - 2006 Dreamer Nom,
zones
C4 x86 assembler and some C emulation code
(c) Copyright 2000 - 2003 _Demo_ ([email protected]),
Nach,
zsKnight ([email protected])
C4 C++ code
(c) Copyright 2003 - 2006 Brad Jorsch,
Nach
DSP-1 emulator code
(c) Copyright 1998 - 2006 _Demo_,
Andreas Naive ([email protected])
Gary Henderson,
Ivar ([email protected]),
John Weidman,
Kris Bleakley,
Matthew Kendora,
Nach,
neviksti ([email protected])
DSP-2 emulator code
(c) Copyright 2003 John Weidman,
Kris Bleakley,
Lord Nightmare ([email protected]),
Matthew Kendora,
neviksti
DSP-3 emulator code
(c) Copyright 2003 - 2006 John Weidman,
Kris Bleakley,
Lancer,
z80 gaiden
DSP-4 emulator code
(c) Copyright 2004 - 2006 Dreamer Nom,
John Weidman,
Kris Bleakley,
Nach,
z80 gaiden
OBC1 emulator code
(c) Copyright 2001 - 2004 zsKnight,
pagefault ([email protected]),
Kris Bleakley,
Ported from x86 assembler to C by sanmaiwashi
SPC7110 and RTC C++ emulator code
(c) Copyright 2002 Matthew Kendora with research by
zsKnight,
John Weidman,
Dark Force
S-DD1 C emulator code
(c) Copyright 2003 Brad Jorsch with research by
Andreas Naive,
John Weidman
S-RTC C emulator code
(c) Copyright 2001-2006 byuu,
John Weidman
ST010 C++ emulator code
(c) Copyright 2003 Feather,
John Weidman,
Kris Bleakley,
Matthew Kendora
Super FX x86 assembler emulator code
(c) Copyright 1998 - 2003 _Demo_,
pagefault,
zsKnight,
Super FX C emulator code
(c) Copyright 1997 - 1999 Ivar,
Gary Henderson,
John Weidman
Sound DSP emulator code is derived from SNEeSe and OpenSPC:
(c) Copyright 1998 - 2003 Brad Martin
(c) Copyright 1998 - 2006 Charles Bilyue'
SH assembler code partly based on x86 assembler code
(c) Copyright 2002 - 2004 Marcus Comstedt ([email protected])
2xSaI filter
(c) Copyright 1999 - 2001 Derek Liauw Kie Fa
HQ2x, HQ3x, HQ4x filters
(c) Copyright 2003 Maxim Stepin ([email protected])
Win32 GUI code
(c) Copyright 2003 - 2006 blip,
funkyass,
Matthew Kendora,
Nach,
nitsuja
Mac OS GUI code
(c) Copyright 1998 - 2001 John Stiles
(c) Copyright 2001 - 2007 zones
Specific ports contains the works of other authors. See headers in
individual files.
Snes9x homepage: http://www.snes9x.com
Permission to use, copy, modify and/or distribute Snes9x in both binary
and source form, for non-commercial purposes, is hereby granted without
fee, providing that this license information and copyright notice appear
with all copies and any derived work.
This software is provided 'as-is', without any express or implied
warranty. In no event shall the authors be held liable for any damages
arising from the use of this software or it's derivatives.
Snes9x is freeware for PERSONAL USE only. Commercial users should
seek permission of the copyright holders first. Commercial use includes,
but is not limited to, charging money for Snes9x or software derived from
Snes9x, including Snes9x or derivatives in commercial game bundles, and/or
using Snes9x as a promotion for your commercial product.
The copyright holders request that bug fixes and improvements to the code
should be forwarded to them so everyone can benefit from the modifications
in future versions.
Super NES and Super Nintendo Entertainment System are trademarks of
Nintendo Co., Limited and its subsidiary companies.
**********************************************************************************/
#include "snes9x.h"
#include "memmap.h"
#include <string.h>
/*
Due recognition and credit are given on Overload's DSP website.
Thank those contributors for their hard work on this chip.
Fixed-point math reminder:
[sign, integer, fraction]
1.15.00 * 1.15.00 = 2.30.00 -> 1.30.00 (DSP) -> 1.31.00 (LSB is '0')
1.15.00 * 1.00.15 = 2.15.15 -> 1.15.15 (DSP) -> 1.15.16 (LSB is '0')
*/
typedef struct
{
bool8 waiting4command;
bool8 half_command;
uint16 command;
uint32 in_count;
uint32 in_index;
uint32 out_count;
uint32 out_index;
uint8 parameters[512];
uint8 output[512];
} SDSP4;
SDSP4 DSP4;
//Todo: get all of this into a struct for easy save stating
// op control
int8 DSP4_Logic; // controls op flow
// projection format
int16 lcv; // loop-control variable
int16 distance; // z-position into virtual world
int16 raster; // current raster line
int16 segments; // number of raster lines drawn
// 1.15.16 or 1.15.0 [sign, integer, fraction]
int32 world_x; // line of x-projection in world
int32 world_y; // line of y-projection in world
int32 world_dx; // projection line x-delta
int32 world_dy; // projection line y-delta
int16 world_ddx; // x-delta increment
int16 world_ddy; // y-delta increment
int32 world_xenv; // world x-shaping factor
int16 world_yofs; // world y-vertical scroll
int16 view_x1; // current viewer-x
int16 view_y1; // current viewer-y
int16 view_x2; // future viewer-x
int16 view_y2; // future viewer-y
int16 view_dx; // view x-delta factor
int16 view_dy; // view y-delta factor
int16 view_xofs1; // current viewer x-vertical scroll
int16 view_yofs1; // current viewer y-vertical scroll
int16 view_xofs2; // future viewer x-vertical scroll
int16 view_yofs2; // future viewer y-vertical scroll
int16 view_yofsenv; // y-scroll shaping factor
int16 view_turnoff_x; // road turnoff data
int16 view_turnoff_dx; // road turnoff delta factor
// drawing area
int16 viewport_cx; // x-center of viewport window
int16 viewport_cy; // y-center of render window
int16 viewport_left; // x-left of viewport
int16 viewport_right; // x-right of viewport
int16 viewport_top; // y-top of viewport
int16 viewport_bottom; // y-bottom of viewport
// sprite structure
int16 sprite_x; // projected x-pos of sprite
int16 sprite_y; // projected y-pos of sprite
int16 sprite_attr; // obj attributes
bool8 sprite_size; // sprite size: 8x8 or 16x16
int16 sprite_clipy; // visible line to clip pixels off
int16 sprite_count;
// generic projection variables designed for
// two solid polygons + two polygon sides
int16 poly_clipLf[2][2]; // left clip boundary
int16 poly_clipRt[2][2]; // right clip boundary
int16 poly_ptr[2][2]; // HDMA structure pointers
int16 poly_raster[2][2]; // current raster line below horizon
int16 poly_top[2][2]; // top clip boundary
int16 poly_bottom[2][2]; // bottom clip boundary
int16 poly_cx[2][2]; // center for left/right points
int16 poly_start[2]; // current projection points
int16 poly_plane[2]; // previous z-plane distance
// OAM
int16 OAM_attr[16]; // OAM (size,MSB) data
int16 OAM_index; // index into OAM table
int16 OAM_bits; // offset into OAM table
int16 OAM_RowMax; // maximum number of tiles per 8 aligned pixels (row)
int16 OAM_Row[32]; // current number of tiles per row
//////////////////////////////////////////////////////////////
// input protocol
static int16 DSP4_READ_WORD()
{
int16 out;
out = READ_WORD(DSP4.parameters + DSP4.in_index);
DSP4.in_index += 2;
return out;
}
static int32 DSP4_READ_DWORD()
{
int32 out;
out = READ_DWORD(DSP4.parameters + DSP4.in_index);
DSP4.in_index += 4;
return out;
}
//////////////////////////////////////////////////////////////
// output protocol
#define DSP4_CLEAR_OUT() \
{ DSP4.out_count = 0; DSP4.out_index = 0; }
#define DSP4_WRITE_BYTE( d ) \
{ WRITE_WORD( DSP4.output + DSP4.out_count, ( d ) ); DSP4.out_count++; }
#define DSP4_WRITE_WORD( d ) \
{ WRITE_WORD( DSP4.output + DSP4.out_count, ( d ) ); DSP4.out_count += 2; }
#ifndef MSB_FIRST
#define DSP4_WRITE_16_WORD( d ) \
{ memcpy(DSP4.output + DSP4.out_count, ( d ), 32); DSP4.out_count += 32; }
#else
#define DSP4_WRITE_16_WORD( d ) \
{ for (int p = 0; p < 16; p++) DSP4_WRITE_WORD((d)[p]); }
#endif
#ifdef PRINT_OP
#define DSP4_WRITE_DEBUG( x, d ) \
WRITE_WORD( nop + x, d );
#endif
#ifdef DEBUG_DSP
#define DSP4_WRITE_DEBUG( x, d ) \
WRITE_WORD( nop + x, d );
#endif
//////////////////////////////////////////////////////////////
// used to wait for dsp i/o
#define DSP4_WAIT( x ) \
DSP4.in_index = 0; DSP4_Logic = x; return;
//////////////////////////////////////////////////////////////
// 1.7.8 -> 1.15.16
#define SEX78( a ) ( ( (int32) ( (int16) (a) ) ) << 8 )
// 1.15.0 -> 1.15.16
#define SEX16( a ) ( ( (int32) ( (int16) (a) ) ) << 16 )
#ifdef PRINT_OP
#define U16( a ) ( (uint16) ( a ) )
#endif
#ifdef DEBUG_DSP
#define U16( a ) ( (uint16) ( a ) )
#endif
//////////////////////////////////////////////////////////////
// Attention: This lookup table is not verified
const uint16 div_lut[64] = { 0x0000, 0x8000, 0x4000, 0x2aaa, 0x2000, 0x1999, 0x1555, 0x1249, 0x1000, 0x0e38,
0x0ccc, 0x0ba2, 0x0aaa, 0x09d8, 0x0924, 0x0888, 0x0800, 0x0787, 0x071c, 0x06bc,
0x0666, 0x0618, 0x05d1, 0x0590, 0x0555, 0x051e, 0x04ec, 0x04bd, 0x0492, 0x0469,
0x0444, 0x0421, 0x0400, 0x03e0, 0x03c3, 0x03a8, 0x038e, 0x0375, 0x035e, 0x0348,
0x0333, 0x031f, 0x030c, 0x02fa, 0x02e8, 0x02d8, 0x02c8, 0x02b9, 0x02aa, 0x029c,
0x028f, 0x0282, 0x0276, 0x026a, 0x025e, 0x0253, 0x0249, 0x023e, 0x0234, 0x022b,
0x0222, 0x0219, 0x0210, 0x0208, };
int16 DSP4_Inverse(int16 value)
{
// saturate bounds
if (value < 0)
{
value = 0;
}
if (value > 63)
{
value = 63;
}
return div_lut[value];
}
//////////////////////////////////////////////////////////////
// Prototype
void DSP4_OP0B(bool8 *draw, int16 sp_x, int16 sp_y, int16 sp_attr, bool8 size, bool8 stop);
//////////////////////////////////////////////////////////////
// OP00
void DSP4_Multiply(int16 Multiplicand, int16 Multiplier, int32 *Product)
{
*Product = (Multiplicand * Multiplier << 1) >> 1;
}
//////////////////////////////////////////////////////////////
void DSP4_OP01()
{
DSP4.waiting4command = FALSE;
// op flow control
switch (DSP4_Logic)
{
case 1:
goto resume1; break;
case 2:
goto resume2; break;
case 3:
goto resume3; break;
}
////////////////////////////////////////////////////
// process initial inputs
// sort inputs
world_y = DSP4_READ_DWORD();
poly_bottom[0][0] = DSP4_READ_WORD();
poly_top[0][0] = DSP4_READ_WORD();
poly_cx[1][0] = DSP4_READ_WORD();
viewport_bottom = DSP4_READ_WORD();
world_x = DSP4_READ_DWORD();
poly_cx[0][0] = DSP4_READ_WORD();
poly_ptr[0][0] = DSP4_READ_WORD();
world_yofs = DSP4_READ_WORD();
world_dy = DSP4_READ_DWORD();
world_dx = DSP4_READ_DWORD();
distance = DSP4_READ_WORD();
DSP4_READ_WORD(); // 0x0000
world_xenv = DSP4_READ_DWORD();
world_ddy = DSP4_READ_WORD();
world_ddx = DSP4_READ_WORD();
view_yofsenv = DSP4_READ_WORD();
// initial (x,y,offset) at starting raster line
view_x1 = (world_x + world_xenv) >> 16;
view_y1 = world_y >> 16;
view_xofs1 = world_x >> 16;
view_yofs1 = world_yofs;
view_turnoff_x = 0;
view_turnoff_dx = 0;
// first raster line
poly_raster[0][0] = poly_bottom[0][0];
do
{
////////////////////////////////////////////////////
// process one iteration of projection
// perspective projection of world (x,y,scroll) points
// based on the current projection lines
view_x2 = ( ( ( world_x + world_xenv ) >> 16 ) * distance >> 15 ) + ( view_turnoff_x * distance >> 15 );
view_y2 = (world_y >> 16) * distance >> 15;
view_xofs2 = view_x2;
view_yofs2 = (world_yofs * distance >> 15) + poly_bottom[0][0] - view_y2;
// 1. World x-location before transformation
// 2. Viewer x-position at the next
// 3. World y-location before perspective projection
// 4. Viewer y-position below the horizon
// 5. Number of raster lines drawn in this iteration
DSP4_CLEAR_OUT();
DSP4_WRITE_WORD((world_x + world_xenv) >> 16);
DSP4_WRITE_WORD(view_x2);
DSP4_WRITE_WORD(world_y >> 16);
DSP4_WRITE_WORD(view_y2);
//////////////////////////////////////////////////////
// SR = 0x00
// determine # of raster lines used
segments = poly_raster[0][0] - view_y2;
// prevent overdraw
if (view_y2 >= poly_raster[0][0])
segments = 0;
else
poly_raster[0][0] = view_y2;
// don't draw outside the window
if (view_y2 < poly_top[0][0])
{
segments = 0;
// flush remaining raster lines
if (view_y1 >= poly_top[0][0])
segments = view_y1 - poly_top[0][0];
}
// SR = 0x80
DSP4_WRITE_WORD(segments);
//////////////////////////////////////////////////////
// scan next command if no SR check needed
if (segments)
{
int32 px_dx, py_dy;
int32 x_scroll, y_scroll;
// SR = 0x00
// linear interpolation (lerp) between projected points
px_dx = (view_xofs2 - view_xofs1) * DSP4_Inverse(segments) << 1;
py_dy = (view_yofs2 - view_yofs1) * DSP4_Inverse(segments) << 1;
// starting step values
x_scroll = SEX16(poly_cx[0][0] + view_xofs1);
y_scroll = SEX16(-viewport_bottom + view_yofs1 + view_yofsenv + poly_cx[1][0] - world_yofs);
// SR = 0x80
// rasterize line
for (lcv = 0; lcv < segments; lcv++)
{
// 1. HDMA memory pointer (bg1)
// 2. vertical scroll offset ($210E)
// 3. horizontal scroll offset ($210D)
DSP4_WRITE_WORD(poly_ptr[0][0]);
DSP4_WRITE_WORD((y_scroll + 0x8000) >> 16);
DSP4_WRITE_WORD((x_scroll + 0x8000) >> 16);
// update memory address
poly_ptr[0][0] -= 4;
// update screen values
x_scroll += px_dx;
y_scroll += py_dy;
}
}
////////////////////////////////////////////////////
// Post-update
// update new viewer (x,y,scroll) to last raster line drawn
view_x1 = view_x2;
view_y1 = view_y2;
view_xofs1 = view_xofs2;
view_yofs1 = view_yofs2;
// add deltas for projection lines
world_dx += SEX78(world_ddx);
world_dy += SEX78(world_ddy);
// update projection lines
world_x += (world_dx + world_xenv);
world_y += world_dy;
// update road turnoff position
view_turnoff_x += view_turnoff_dx;
////////////////////////////////////////////////////
// command check
// scan next command
DSP4.in_count = 2;
DSP4_WAIT(1) resume1 :
// check for termination
distance = DSP4_READ_WORD();
if (distance == -0x8000)
break;
// road turnoff
if( (uint16) distance == 0x8001 )
{
DSP4.in_count = 6;
DSP4_WAIT(2) resume2:
distance = DSP4_READ_WORD();
view_turnoff_x = DSP4_READ_WORD();
view_turnoff_dx = DSP4_READ_WORD();
// factor in new changes
view_x1 += ( view_turnoff_x * distance >> 15 );
view_xofs1 += ( view_turnoff_x * distance >> 15 );
// update stepping values
view_turnoff_x += view_turnoff_dx;
DSP4.in_count = 2;
DSP4_WAIT(1)
}
// already have 2 bytes read
DSP4.in_count = 6;
DSP4_WAIT(3) resume3 :
// inspect inputs
world_ddy = DSP4_READ_WORD();
world_ddx = DSP4_READ_WORD();
view_yofsenv = DSP4_READ_WORD();
// no envelope here
world_xenv = 0;
}
while (1);
// terminate op
DSP4.waiting4command = TRUE;
}
//////////////////////////////////////////////////////////////
void DSP4_OP03()
{
OAM_RowMax = 33;
memset(OAM_Row, 0, 64);
}
//////////////////////////////////////////////////////////////
void DSP4_OP05()
{
OAM_index = 0;
OAM_bits = 0;
memset(OAM_attr, 0, 32);
sprite_count = 0;
}
//////////////////////////////////////////////////////////////
void DSP4_OP06()
{
DSP4_CLEAR_OUT();
DSP4_WRITE_16_WORD(OAM_attr);
}
//////////////////////////////////////////////////////////////
void DSP4_OP07()
{
DSP4.waiting4command = FALSE;
// op flow control
switch (DSP4_Logic)
{
case 1:
goto resume1; break;
case 2:
goto resume2; break;
}
////////////////////////////////////////////////////
// sort inputs
world_y = DSP4_READ_DWORD();
poly_bottom[0][0] = DSP4_READ_WORD();
poly_top[0][0] = DSP4_READ_WORD();
poly_cx[1][0] = DSP4_READ_WORD();
viewport_bottom = DSP4_READ_WORD();
world_x = DSP4_READ_DWORD();
poly_cx[0][0] = DSP4_READ_WORD();
poly_ptr[0][0] = DSP4_READ_WORD();
world_yofs = DSP4_READ_WORD();
distance = DSP4_READ_WORD();
view_y2 = DSP4_READ_WORD();
view_dy = DSP4_READ_WORD() * distance >> 15;
view_x2 = DSP4_READ_WORD();
view_dx = DSP4_READ_WORD() * distance >> 15;
view_yofsenv = DSP4_READ_WORD();
// initial (x,y,offset) at starting raster line
view_x1 = world_x >> 16;
view_y1 = world_y >> 16;
view_xofs1 = view_x1;
view_yofs1 = world_yofs;
// first raster line
poly_raster[0][0] = poly_bottom[0][0];
do
{
////////////////////////////////////////////////////
// process one iteration of projection
// add shaping
view_x2 += view_dx;
view_y2 += view_dy;
// vertical scroll calculation
view_xofs2 = view_x2;
view_yofs2 = (world_yofs * distance >> 15) + poly_bottom[0][0] - view_y2;
// 1. Viewer x-position at the next
// 2. Viewer y-position below the horizon
// 3. Number of raster lines drawn in this iteration
DSP4_CLEAR_OUT();
DSP4_WRITE_WORD(view_x2);
DSP4_WRITE_WORD(view_y2);
//////////////////////////////////////////////////////
// SR = 0x00
// determine # of raster lines used
segments = view_y1 - view_y2;
// prevent overdraw
if (view_y2 >= poly_raster[0][0])
segments = 0;
else
poly_raster[0][0] = view_y2;
// don't draw outside the window
if (view_y2 < poly_top[0][0])
{
segments = 0;
// flush remaining raster lines
if (view_y1 >= poly_top[0][0])
segments = view_y1 - poly_top[0][0];
}
// SR = 0x80
DSP4_WRITE_WORD(segments);
//////////////////////////////////////////////////////
// scan next command if no SR check needed
if (segments)
{
int32 px_dx, py_dy;
int32 x_scroll, y_scroll;
// SR = 0x00
// linear interpolation (lerp) between projected points
px_dx = (view_xofs2 - view_xofs1) * DSP4_Inverse(segments) << 1;
py_dy = (view_yofs2 - view_yofs1) * DSP4_Inverse(segments) << 1;
// starting step values
x_scroll = SEX16(poly_cx[0][0] + view_xofs1);
y_scroll = SEX16(-viewport_bottom + view_yofs1 + view_yofsenv + poly_cx[1][0] - world_yofs);
// SR = 0x80
// rasterize line
for (lcv = 0; lcv < segments; lcv++)
{
// 1. HDMA memory pointer (bg2)
// 2. vertical scroll offset ($2110)
// 3. horizontal scroll offset ($210F)
DSP4_WRITE_WORD(poly_ptr[0][0]);
DSP4_WRITE_WORD((y_scroll + 0x8000) >> 16);
DSP4_WRITE_WORD((x_scroll + 0x8000) >> 16);
// update memory address
poly_ptr[0][0] -= 4;
// update screen values
x_scroll += px_dx;
y_scroll += py_dy;
}
}
/////////////////////////////////////////////////////
// Post-update
// update new viewer (x,y,scroll) to last raster line drawn
view_x1 = view_x2;
view_y1 = view_y2;
view_xofs1 = view_xofs2;
view_yofs1 = view_yofs2;
////////////////////////////////////////////////////
// command check
// scan next command
DSP4.in_count = 2;
DSP4_WAIT(1) resume1 :
// check for opcode termination
distance = DSP4_READ_WORD();
if (distance == -0x8000)
break;
// already have 2 bytes in queue
DSP4.in_count = 10;
DSP4_WAIT(2) resume2 :
// inspect inputs
view_y2 = DSP4_READ_WORD();
view_dy = DSP4_READ_WORD() * distance >> 15;
view_x2 = DSP4_READ_WORD();
view_dx = DSP4_READ_WORD() * distance >> 15;
view_yofsenv = DSP4_READ_WORD();
}
while (1);
DSP4.waiting4command = TRUE;
}
//////////////////////////////////////////////////////////////
void DSP4_OP08()
{
int16 win_left, win_right;
int16 view_x[2], view_y[2];
int16 envelope[2][2];
DSP4.waiting4command = FALSE;
// op flow control
switch (DSP4_Logic)
{
case 1:
goto resume1; break;
case 2:
goto resume2; break;
}
////////////////////////////////////////////////////
// process initial inputs for two polygons
// clip values
poly_clipRt[0][0] = DSP4_READ_WORD();
poly_clipRt[0][1] = DSP4_READ_WORD();
poly_clipRt[1][0] = DSP4_READ_WORD();
poly_clipRt[1][1] = DSP4_READ_WORD();
poly_clipLf[0][0] = DSP4_READ_WORD();
poly_clipLf[0][1] = DSP4_READ_WORD();
poly_clipLf[1][0] = DSP4_READ_WORD();
poly_clipLf[1][1] = DSP4_READ_WORD();
// unknown (constant) (ex. 1P/2P = $00A6, $00A6, $00A6, $00A6)
DSP4_READ_WORD();
DSP4_READ_WORD();
DSP4_READ_WORD();
DSP4_READ_WORD();
// unknown (constant) (ex. 1P/2P = $00A5, $00A5, $00A7, $00A7)
DSP4_READ_WORD();
DSP4_READ_WORD();
DSP4_READ_WORD();
DSP4_READ_WORD();
// polygon centering (left,right)
poly_cx[0][0] = DSP4_READ_WORD();
poly_cx[0][1] = DSP4_READ_WORD();
poly_cx[1][0] = DSP4_READ_WORD();
poly_cx[1][1] = DSP4_READ_WORD();
// HDMA pointer locations
poly_ptr[0][0] = DSP4_READ_WORD();
poly_ptr[0][1] = DSP4_READ_WORD();
poly_ptr[1][0] = DSP4_READ_WORD();
poly_ptr[1][1] = DSP4_READ_WORD();
// starting raster line below the horizon
poly_bottom[0][0] = DSP4_READ_WORD();
poly_bottom[0][1] = DSP4_READ_WORD();
poly_bottom[1][0] = DSP4_READ_WORD();
poly_bottom[1][1] = DSP4_READ_WORD();
// top boundary line to clip
poly_top[0][0] = DSP4_READ_WORD();
poly_top[0][1] = DSP4_READ_WORD();
poly_top[1][0] = DSP4_READ_WORD();
poly_top[1][1] = DSP4_READ_WORD();
// unknown
// (ex. 1P = $2FC8, $0034, $FF5C, $0035)
//
// (ex. 2P = $3178, $0034, $FFCC, $0035)
// (ex. 2P = $2FC8, $0034, $FFCC, $0035)
DSP4_READ_WORD();
DSP4_READ_WORD();
DSP4_READ_WORD();
DSP4_READ_WORD();
// look at guidelines for both polygon shapes
distance = DSP4_READ_WORD();
view_x[0] = DSP4_READ_WORD();
view_y[0] = DSP4_READ_WORD();
view_x[1] = DSP4_READ_WORD();
view_y[1] = DSP4_READ_WORD();
// envelope shaping guidelines (one frame only)
envelope[0][0] = DSP4_READ_WORD();
envelope[0][1] = DSP4_READ_WORD();
envelope[1][0] = DSP4_READ_WORD();
envelope[1][1] = DSP4_READ_WORD();
// starting base values to project from
poly_start[0] = view_x[0];
poly_start[1] = view_x[1];
// starting raster lines to begin drawing
poly_raster[0][0] = view_y[0];
poly_raster[0][1] = view_y[0];
poly_raster[1][0] = view_y[1];
poly_raster[1][1] = view_y[1];
// starting distances
poly_plane[0] = distance;
poly_plane[1] = distance;
// SR = 0x00
// re-center coordinates
win_left = poly_cx[0][0] - view_x[0] + envelope[0][0];
win_right = poly_cx[0][1] - view_x[0] + envelope[0][1];
// saturate offscreen data for polygon #1
if (win_left < poly_clipLf[0][0])
{
win_left = poly_clipLf[0][0];
}
if (win_left > poly_clipRt[0][0])
{
win_left = poly_clipRt[0][0];
}
if (win_right < poly_clipLf[0][1])
{
win_right = poly_clipLf[0][1];
}
if (win_right > poly_clipRt[0][1])
{
win_right = poly_clipRt[0][1];
}
// SR = 0x80
// initial output for polygon #1
DSP4_CLEAR_OUT();
DSP4_WRITE_BYTE(win_left & 0xff);
DSP4_WRITE_BYTE(win_right & 0xff);
do
{
int16 polygon;
////////////////////////////////////////////////////
// command check
// scan next command
DSP4.in_count = 2;
DSP4_WAIT(1) resume1 :
// terminate op
distance = DSP4_READ_WORD();
if (distance == -0x8000)
break;
// already have 2 bytes in queue
DSP4.in_count = 16;
DSP4_WAIT(2) resume2 :
// look at guidelines for both polygon shapes
view_x[0] = DSP4_READ_WORD();
view_y[0] = DSP4_READ_WORD();
view_x[1] = DSP4_READ_WORD();
view_y[1] = DSP4_READ_WORD();
// envelope shaping guidelines (one frame only)
envelope[0][0] = DSP4_READ_WORD();
envelope[0][1] = DSP4_READ_WORD();
envelope[1][0] = DSP4_READ_WORD();
envelope[1][1] = DSP4_READ_WORD();
////////////////////////////////////////////////////
// projection begins
// init
DSP4_CLEAR_OUT();
//////////////////////////////////////////////
// solid polygon renderer - 2 shapes
for (polygon = 0; polygon < 2; polygon++)
{
int32 left_inc, right_inc;
int16 x1_final, x2_final;
int16 env[2][2];
int16 poly;
// SR = 0x00
// # raster lines to draw
segments = poly_raster[polygon][0] - view_y[polygon];