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dsp4.cpp
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dsp4.cpp
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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 - 2010 Brad Jorsch ([email protected]),
Nach ([email protected]),
(c) Copyright 2002 - 2011 zones ([email protected])
(c) Copyright 2006 - 2007 nitsuja
(c) Copyright 2009 - 2016 BearOso,
OV2
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 used in 1.39-1.51
(c) Copyright 2002 Matthew Kendora with research by
zsKnight,
John Weidman,
Dark Force
SPC7110 and RTC C++ emulator code used in 1.52+
(c) Copyright 2009 byuu,
neviksti
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 emulator code used in 1.5-1.51
(c) Copyright 1998 - 2003 Brad Martin
(c) Copyright 1998 - 2006 Charles Bilyue'
Sound emulator code used in 1.52+
(c) Copyright 2004 - 2007 Shay Green ([email protected])
S-SMP emulator code used in 1.54+
(c) Copyright 2016 byuu
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])
NTSC filter
(c) Copyright 2006 - 2007 Shay Green
GTK+ GUI code
(c) Copyright 2004 - 2016 BearOso
Win32 GUI code
(c) Copyright 2003 - 2006 blip,
funkyass,
Matthew Kendora,
Nach,
nitsuja
(c) Copyright 2009 - 2016 OV2
Mac OS GUI code
(c) Copyright 1998 - 2001 John Stiles
(c) Copyright 2001 - 2011 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.
***********************************************************************************/
/*
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')
*/
#include "snes9x.h"
#include "memmap.h"
#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
// 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)
static int16 DSP4_READ_WORD (void);
static int32 DSP4_READ_DWORD (void);
static int16 DSP4_Inverse (int16);
static void DSP4_Multiply (int16, int16, int32 *);
static void DSP4_OP01 (void);
static void DSP4_OP03 (void);
static void DSP4_OP05 (void);
static void DSP4_OP06 (void);
static void DSP4_OP07 (void);
static void DSP4_OP08 (void);
static void DSP4_OP09 (void);
static void DSP4_OP0A (int16, int16 *, int16 *, int16 *, int16 *);
static void DSP4_OP0B (bool8 *, int16, int16, int16, bool8, bool8);
static void DSP4_OP0D (void);
static void DSP4_OP0E (void);
static void DSP4_OP0F (void);
static void DSP4_OP10 (void);
static void DSP4_OP11 (int16, int16, int16, int16, int16 *);
static void DSP4_SetByte (void);
static void DSP4_GetByte (void);
static int16 DSP4_READ_WORD (void)
{
int16 out;
out = READ_WORD(DSP4.parameters + DSP4.in_index);
DSP4.in_index += 2;
return (out);
}
static int32 DSP4_READ_DWORD (void)
{
int32 out;
out = READ_DWORD(DSP4.parameters + DSP4.in_index);
DSP4.in_index += 4;
return (out);
}
static int16 DSP4_Inverse (int16 value)
{
// 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
};
// saturate bounds
if (value < 0)
value = 0;
if (value > 63)
value = 63;
return (div_lut[value]);
}
static void DSP4_Multiply (int16 Multiplicand, int16 Multiplier, int32 *Product)
{
*Product = (Multiplicand * Multiplier << 1) >> 1;
}
static void DSP4_OP01 (void)
{
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
DSP4.world_y = DSP4_READ_DWORD();
DSP4.poly_bottom[0][0] = DSP4_READ_WORD();
DSP4.poly_top[0][0] = DSP4_READ_WORD();
DSP4.poly_cx[1][0] = DSP4_READ_WORD();
DSP4.viewport_bottom = DSP4_READ_WORD();
DSP4.world_x = DSP4_READ_DWORD();
DSP4.poly_cx[0][0] = DSP4_READ_WORD();
DSP4.poly_ptr[0][0] = DSP4_READ_WORD();
DSP4.world_yofs = DSP4_READ_WORD();
DSP4.world_dy = DSP4_READ_DWORD();
DSP4.world_dx = DSP4_READ_DWORD();
DSP4.distance = DSP4_READ_WORD();
DSP4_READ_WORD(); // 0x0000
DSP4.world_xenv = DSP4_READ_DWORD();
DSP4.world_ddy = DSP4_READ_WORD();
DSP4.world_ddx = DSP4_READ_WORD();
DSP4.view_yofsenv = DSP4_READ_WORD();
// initial (x, y, offset) at starting raster line
DSP4.view_x1 = (DSP4.world_x + DSP4.world_xenv) >> 16;
DSP4.view_y1 = DSP4.world_y >> 16;
DSP4.view_xofs1 = DSP4.world_x >> 16;
DSP4.view_yofs1 = DSP4.world_yofs;
DSP4.view_turnoff_x = 0;
DSP4.view_turnoff_dx = 0;
// first raster line
DSP4.poly_raster[0][0] = DSP4.poly_bottom[0][0];
do
{
////////////////////////////////////////////////////
// process one iteration of projection
// perspective projection of world (x, y, scroll) points
// based on the current projection lines
DSP4.view_x2 = (((DSP4.world_x + DSP4.world_xenv) >> 16) * DSP4.distance >> 15) + (DSP4.view_turnoff_x * DSP4.distance >> 15);
DSP4.view_y2 = (DSP4.world_y >> 16) * DSP4.distance >> 15;
DSP4.view_xofs2 = DSP4.view_x2;
DSP4.view_yofs2 = (DSP4.world_yofs * DSP4.distance >> 15) + DSP4.poly_bottom[0][0] - DSP4.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((DSP4.world_x + DSP4.world_xenv) >> 16);
DSP4_WRITE_WORD(DSP4.view_x2);
DSP4_WRITE_WORD(DSP4.world_y >> 16);
DSP4_WRITE_WORD(DSP4.view_y2);
//////////////////////////////////////////////////////
// SR = 0x00
// determine # of raster lines used
DSP4.segments = DSP4.poly_raster[0][0] - DSP4.view_y2;
// prevent overdraw
if (DSP4.view_y2 >= DSP4.poly_raster[0][0])
DSP4.segments = 0;
else
DSP4.poly_raster[0][0] = DSP4.view_y2;
// don't draw outside the window
if (DSP4.view_y2 < DSP4.poly_top[0][0])
{
DSP4.segments = 0;
// flush remaining raster lines
if (DSP4.view_y1 >= DSP4.poly_top[0][0])
DSP4.segments = DSP4.view_y1 - DSP4.poly_top[0][0];
}
// SR = 0x80
DSP4_WRITE_WORD(DSP4.segments);
//////////////////////////////////////////////////////
// scan next command if no SR check needed
if (DSP4.segments)
{
int32 px_dx, py_dy;
int32 x_scroll, y_scroll;
// SR = 0x00
// linear interpolation (lerp) between projected points
px_dx = (DSP4.view_xofs2 - DSP4.view_xofs1) * DSP4_Inverse(DSP4.segments) << 1;
py_dy = (DSP4.view_yofs2 - DSP4.view_yofs1) * DSP4_Inverse(DSP4.segments) << 1;
// starting step values
x_scroll = SEX16(DSP4.poly_cx[0][0] + DSP4.view_xofs1);
y_scroll = SEX16(-DSP4.viewport_bottom + DSP4.view_yofs1 + DSP4.view_yofsenv + DSP4.poly_cx[1][0] - DSP4.world_yofs);
// SR = 0x80
// rasterize line
for (DSP4.lcv = 0; DSP4.lcv < DSP4.segments; DSP4.lcv++)
{
// 1. HDMA memory pointer (bg1)
// 2. vertical scroll offset ($210E)
// 3. horizontal scroll offset ($210D)
DSP4_WRITE_WORD(DSP4.poly_ptr[0][0]);
DSP4_WRITE_WORD((y_scroll + 0x8000) >> 16);
DSP4_WRITE_WORD((x_scroll + 0x8000) >> 16);
// update memory address
DSP4.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
DSP4.view_x1 = DSP4.view_x2;
DSP4.view_y1 = DSP4.view_y2;
DSP4.view_xofs1 = DSP4.view_xofs2;
DSP4.view_yofs1 = DSP4.view_yofs2;
// add deltas for projection lines
DSP4.world_dx += SEX78(DSP4.world_ddx);
DSP4.world_dy += SEX78(DSP4.world_ddy);
// update projection lines
DSP4.world_x += (DSP4.world_dx + DSP4.world_xenv);
DSP4.world_y += DSP4.world_dy;
// update road turnoff position
DSP4.view_turnoff_x += DSP4.view_turnoff_dx;
////////////////////////////////////////////////////
// command check
// scan next command
DSP4.in_count = 2;
DSP4_WAIT(1);
resume1:
// check for termination
DSP4.distance = DSP4_READ_WORD();
if (DSP4.distance == -0x8000)
break;
// road turnoff
if ((uint16) DSP4.distance == 0x8001)
{
DSP4.in_count = 6;
DSP4_WAIT(2);
resume2:
DSP4.distance = DSP4_READ_WORD();
DSP4.view_turnoff_x = DSP4_READ_WORD();
DSP4.view_turnoff_dx = DSP4_READ_WORD();
// factor in new changes
DSP4.view_x1 += (DSP4.view_turnoff_x * DSP4.distance >> 15);
DSP4.view_xofs1 += (DSP4.view_turnoff_x * DSP4.distance >> 15);
// update stepping values
DSP4.view_turnoff_x += DSP4.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
DSP4.world_ddy = DSP4_READ_WORD();
DSP4.world_ddx = DSP4_READ_WORD();
DSP4.view_yofsenv = DSP4_READ_WORD();
// no envelope here
DSP4.world_xenv = 0;
}
while (1);
// terminate op
DSP4.waiting4command = TRUE;
}
static void DSP4_OP03 (void)
{
DSP4.OAM_RowMax = 33;
memset(DSP4.OAM_Row, 0, 64);
}
static void DSP4_OP05 (void)
{
DSP4.OAM_index = 0;
DSP4.OAM_bits = 0;
memset(DSP4.OAM_attr, 0, 32);
DSP4.sprite_count = 0;
}
static void DSP4_OP06 (void)
{
DSP4_CLEAR_OUT();
DSP4_WRITE_16_WORD(DSP4.OAM_attr);
}
static void DSP4_OP07 (void)
{
DSP4.waiting4command = FALSE;
// op flow control
switch (DSP4.Logic)
{
case 1: goto resume1; break;
case 2: goto resume2; break;
}
////////////////////////////////////////////////////
// sort inputs
DSP4.world_y = DSP4_READ_DWORD();
DSP4.poly_bottom[0][0] = DSP4_READ_WORD();
DSP4.poly_top[0][0] = DSP4_READ_WORD();
DSP4.poly_cx[1][0] = DSP4_READ_WORD();
DSP4.viewport_bottom = DSP4_READ_WORD();
DSP4.world_x = DSP4_READ_DWORD();
DSP4.poly_cx[0][0] = DSP4_READ_WORD();
DSP4.poly_ptr[0][0] = DSP4_READ_WORD();
DSP4.world_yofs = DSP4_READ_WORD();
DSP4.distance = DSP4_READ_WORD();
DSP4.view_y2 = DSP4_READ_WORD();
DSP4.view_dy = DSP4_READ_WORD() * DSP4.distance >> 15;
DSP4.view_x2 = DSP4_READ_WORD();
DSP4.view_dx = DSP4_READ_WORD() * DSP4.distance >> 15;
DSP4.view_yofsenv = DSP4_READ_WORD();
// initial (x, y, offset) at starting raster line
DSP4.view_x1 = DSP4.world_x >> 16;
DSP4.view_y1 = DSP4.world_y >> 16;
DSP4.view_xofs1 = DSP4.view_x1;
DSP4.view_yofs1 = DSP4.world_yofs;
// first raster line
DSP4.poly_raster[0][0] = DSP4.poly_bottom[0][0];
do
{
////////////////////////////////////////////////////
// process one iteration of projection
// add shaping
DSP4.view_x2 += DSP4.view_dx;
DSP4.view_y2 += DSP4.view_dy;
// vertical scroll calculation
DSP4.view_xofs2 = DSP4.view_x2;
DSP4.view_yofs2 = (DSP4.world_yofs * DSP4.distance >> 15) + DSP4.poly_bottom[0][0] - DSP4.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(DSP4.view_x2);
DSP4_WRITE_WORD(DSP4.view_y2);
//////////////////////////////////////////////////////
// SR = 0x00
// determine # of raster lines used
DSP4.segments = DSP4.view_y1 - DSP4.view_y2;
// prevent overdraw
if (DSP4.view_y2 >= DSP4.poly_raster[0][0])
DSP4.segments = 0;
else
DSP4.poly_raster[0][0] = DSP4.view_y2;
// don't draw outside the window
if (DSP4.view_y2 < DSP4.poly_top[0][0])
{
DSP4.segments = 0;
// flush remaining raster lines
if (DSP4.view_y1 >= DSP4.poly_top[0][0])
DSP4.segments = DSP4.view_y1 - DSP4.poly_top[0][0];
}
// SR = 0x80
DSP4_WRITE_WORD(DSP4.segments);
//////////////////////////////////////////////////////
// scan next command if no SR check needed
if (DSP4.segments)
{
int32 px_dx, py_dy;
int32 x_scroll, y_scroll;
// SR = 0x00
// linear interpolation (lerp) between projected points
px_dx = (DSP4.view_xofs2 - DSP4.view_xofs1) * DSP4_Inverse(DSP4.segments) << 1;
py_dy = (DSP4.view_yofs2 - DSP4.view_yofs1) * DSP4_Inverse(DSP4.segments) << 1;
// starting step values
x_scroll = SEX16(DSP4.poly_cx[0][0] + DSP4.view_xofs1);
y_scroll = SEX16(-DSP4.viewport_bottom + DSP4.view_yofs1 + DSP4.view_yofsenv + DSP4.poly_cx[1][0] - DSP4.world_yofs);
// SR = 0x80
// rasterize line
for (DSP4.lcv = 0; DSP4.lcv < DSP4.segments; DSP4.lcv++)
{
// 1. HDMA memory pointer (bg2)
// 2. vertical scroll offset ($2110)
// 3. horizontal scroll offset ($210F)
DSP4_WRITE_WORD(DSP4.poly_ptr[0][0]);
DSP4_WRITE_WORD((y_scroll + 0x8000) >> 16);
DSP4_WRITE_WORD((x_scroll + 0x8000) >> 16);
// update memory address
DSP4.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
DSP4.view_x1 = DSP4.view_x2;
DSP4.view_y1 = DSP4.view_y2;
DSP4.view_xofs1 = DSP4.view_xofs2;
DSP4.view_yofs1 = DSP4.view_yofs2;
////////////////////////////////////////////////////
// command check
// scan next command
DSP4.in_count = 2;
DSP4_WAIT(1);
resume1:
// check for opcode termination
DSP4.distance = DSP4_READ_WORD();
if (DSP4.distance == -0x8000)
break;
// already have 2 bytes in queue
DSP4.in_count = 10;
DSP4_WAIT(2);
resume2:
// inspect inputs
DSP4.view_y2 = DSP4_READ_WORD();
DSP4.view_dy = DSP4_READ_WORD() * DSP4.distance >> 15;
DSP4.view_x2 = DSP4_READ_WORD();
DSP4.view_dx = DSP4_READ_WORD() * DSP4.distance >> 15;
DSP4.view_yofsenv = DSP4_READ_WORD();
}
while (1);
DSP4.waiting4command = TRUE;
}
static void DSP4_OP08 (void)
{
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
DSP4.poly_clipRt[0][0] = DSP4_READ_WORD();
DSP4.poly_clipRt[0][1] = DSP4_READ_WORD();
DSP4.poly_clipRt[1][0] = DSP4_READ_WORD();
DSP4.poly_clipRt[1][1] = DSP4_READ_WORD();
DSP4.poly_clipLf[0][0] = DSP4_READ_WORD();
DSP4.poly_clipLf[0][1] = DSP4_READ_WORD();
DSP4.poly_clipLf[1][0] = DSP4_READ_WORD();
DSP4.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)
DSP4.poly_cx[0][0] = DSP4_READ_WORD();
DSP4.poly_cx[0][1] = DSP4_READ_WORD();
DSP4.poly_cx[1][0] = DSP4_READ_WORD();
DSP4.poly_cx[1][1] = DSP4_READ_WORD();
// HDMA pointer locations
DSP4.poly_ptr[0][0] = DSP4_READ_WORD();
DSP4.poly_ptr[0][1] = DSP4_READ_WORD();
DSP4.poly_ptr[1][0] = DSP4_READ_WORD();
DSP4.poly_ptr[1][1] = DSP4_READ_WORD();
// starting raster line below the horizon
DSP4.poly_bottom[0][0] = DSP4_READ_WORD();
DSP4.poly_bottom[0][1] = DSP4_READ_WORD();
DSP4.poly_bottom[1][0] = DSP4_READ_WORD();
DSP4.poly_bottom[1][1] = DSP4_READ_WORD();
// top boundary line to clip
DSP4.poly_top[0][0] = DSP4_READ_WORD();
DSP4.poly_top[0][1] = DSP4_READ_WORD();
DSP4.poly_top[1][0] = DSP4_READ_WORD();
DSP4.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
DSP4.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
DSP4.poly_start[0] = view_x[0];
DSP4.poly_start[1] = view_x[1];
// starting raster lines to begin drawing
DSP4.poly_raster[0][0] = view_y[0];
DSP4.poly_raster[0][1] = view_y[0];
DSP4.poly_raster[1][0] = view_y[1];
DSP4.poly_raster[1][1] = view_y[1];
// starting distances
DSP4.poly_plane[0] = DSP4.distance;
DSP4.poly_plane[1] = DSP4.distance;
// SR = 0x00
// re-center coordinates
win_left = DSP4.poly_cx[0][0] - view_x[0] + envelope[0][0];
win_right = DSP4.poly_cx[0][1] - view_x[0] + envelope[0][1];
// saturate offscreen data for polygon #1
if (win_left < DSP4.poly_clipLf[0][0])
win_left = DSP4.poly_clipLf[0][0];
if (win_left > DSP4.poly_clipRt[0][0])
win_left = DSP4.poly_clipRt[0][0];
if (win_right < DSP4.poly_clipLf[0][1])
win_right = DSP4.poly_clipLf[0][1];
if (win_right > DSP4.poly_clipRt[0][1])
win_right = DSP4.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
DSP4.distance = DSP4_READ_WORD();
if (DSP4.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
DSP4.segments = DSP4.poly_raster[polygon][0] - view_y[polygon];
// prevent overdraw
if (DSP4.segments > 0)
{
// bump drawing cursor
DSP4.poly_raster[polygon][0] = view_y[polygon];
DSP4.poly_raster[polygon][1] = view_y[polygon];
}
else
DSP4.segments = 0;
// don't draw outside the window
if (view_y[polygon] < DSP4.poly_top[polygon][0])
{
DSP4.segments = 0;
// flush remaining raster lines
if (view_y[polygon] >= DSP4.poly_top[polygon][0])
DSP4.segments = view_y[polygon] - DSP4.poly_top[polygon][0];
}
// SR = 0x80
// tell user how many raster structures to read in
DSP4_WRITE_WORD(DSP4.segments);
// normal parameters
poly = polygon;
/////////////////////////////////////////////////////
// scan next command if no SR check needed
if (DSP4.segments)
{
int32 w_left, w_right;
// road turnoff selection
if ((uint16) envelope[polygon][0] == (uint16) 0xc001)
poly = 1;
else
if (envelope[polygon][1] == 0x3fff)
poly = 1;
///////////////////////////////////////////////
// left side of polygon
// perspective correction on additional shaping parameters
env[0][0] = envelope[polygon][0] * DSP4.poly_plane[poly] >> 15;
env[0][1] = envelope[polygon][0] * DSP4.distance >> 15;
// project new shapes (left side)
x1_final = view_x[poly] + env[0][0];
x2_final = DSP4.poly_start[poly] + env[0][1];
// interpolate between projected points with shaping
left_inc = (x2_final - x1_final) * DSP4_Inverse(DSP4.segments) << 1;
if (DSP4.segments == 1)
left_inc = -left_inc;
///////////////////////////////////////////////
// right side of polygon
// perspective correction on additional shaping parameters
env[1][0] = envelope[polygon][1] * DSP4.poly_plane[poly] >> 15;
env[1][1] = envelope[polygon][1] * DSP4.distance >> 15;
// project new shapes (right side)
x1_final = view_x[poly] + env[1][0];
x2_final = DSP4.poly_start[poly] + env[1][1];
// interpolate between projected points with shaping
right_inc = (x2_final - x1_final) * DSP4_Inverse(DSP4.segments) << 1;
if (DSP4.segments == 1)
right_inc = -right_inc;
///////////////////////////////////////////////
// update each point on the line
w_left = SEX16(DSP4.poly_cx[polygon][0] - DSP4.poly_start[poly] + env[0][0]);
w_right = SEX16(DSP4.poly_cx[polygon][1] - DSP4.poly_start[poly] + env[1][0]);
// update distance drawn into world
DSP4.poly_plane[polygon] = DSP4.distance;
// rasterize line
for (DSP4.lcv = 0; DSP4.lcv < DSP4.segments; DSP4.lcv++)
{
int16 x_left, x_right;
// project new coordinates
w_left += left_inc;
w_right += right_inc;
// grab integer portion, drop fraction (no rounding)
x_left = w_left >> 16;
x_right = w_right >> 16;
// saturate offscreen data
if (x_left < DSP4.poly_clipLf[polygon][0])
x_left = DSP4.poly_clipLf[polygon][0];
if (x_left > DSP4.poly_clipRt[polygon][0])
x_left = DSP4.poly_clipRt[polygon][0];
if (x_right < DSP4.poly_clipLf[polygon][1])
x_right = DSP4.poly_clipLf[polygon][1];
if (x_right > DSP4.poly_clipRt[polygon][1])
x_right = DSP4.poly_clipRt[polygon][1];
// 1. HDMA memory pointer
// 2. Left window position ($2126/$2128)
// 3. Right window position ($2127/$2129)
DSP4_WRITE_WORD(DSP4.poly_ptr[polygon][0]);
DSP4_WRITE_BYTE(x_left & 0xff);
DSP4_WRITE_BYTE(x_right & 0xff);
// update memory pointers
DSP4.poly_ptr[polygon][0] -= 4;
DSP4.poly_ptr[polygon][1] -= 4;
} // end rasterize line
}
////////////////////////////////////////////////
// Post-update
// new projection spot to continue rasterizing from
DSP4.poly_start[polygon] = view_x[poly];
} // end polygon rasterizer
}
while (1);
// unknown output