/*****************************************************************************/
/* */
/* _antic.h */
/* */
/* Internal include file, do not use directly */
/* */
/* */
/* "ANTIC, Alphanumeric Television Interface Controller, is responsible for */
/* the generation of playfield graphics which is delivered as a datastream */
/* to the related CTIA/GTIA chip. The CTIA/GTIA provides the coloring of the */
/* playfield graphics, and is responsible for adding overlaid sprite */
/* (referred to as "Player/Missile graphics" by Atari). Atari advertised it */
/* as a true microprocessor, in that it has an instruction set to run */
/* programs (called display lists) to process data. ANTIC has no capacity */
/* for writing back computed values to memory, it merely reads data from */
/* memory and processes it for output to the screen, therefore it is not */
/* Turing complete." - Wikipedia article on "ANTIC" (with edits) */
/* */
/* (C) 2000 Freddy Offenga <taf_offenga@yahoo.com> */
/* 24-Jan-2011: Christian Krueger: Added defines for Antic instruction set */
/* 2019-01-16: Bill Kendrick <nbs@sonic.net>: More defines for registers */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
#ifndef __ANTIC_H
#define __ANTIC_H
/*****************************************************************************/
/* Define a structure with the ANTIC coprocessor's register offsets */
/*****************************************************************************/
struct __antic {
unsigned char dmactl; /* (W) direct memory access control */
unsigned char chactl; /* (W) character mode control */
unsigned char dlistl; /* display list pointer low-byte */
unsigned char dlisth; /* display list pointer high-byte */
unsigned char hscrol; /* (W) horizontal scroll enable */
unsigned char vscrol; /* (W) vertical scroll enable */
unsigned char unuse0; /* unused */
unsigned char pmbase; /* (W) msb of p/m base address (for when DMACTL has player and/or missile DMA enabled) */
unsigned char unuse1; /* unused */
unsigned char chbase; /* (W) msb of character set base address */
unsigned char wsync; /* (W) wait for horizontal synchronization */
unsigned char vcount; /* (R) vertical line counter */
unsigned char penh; /* (R) light pen horizontal position */
unsigned char penv; /* (R) light pen vertical position */
unsigned char nmien; /* (W) non-maskable interrupt enable */
union {
/* (W) ("NMIRES") nmi reset -- clears the interrupt request register;
** resets all of the NMI status together
*/
unsigned char nmires;
/* (R) ("NMIST") nmi status -- holds cause for the NMI interrupt */
unsigned char nmist;
};
};
/*****************************************************************************/
/* DMACTL register options */
/*****************************************************************************/
/* Initialized to 0x22: DMA fetch, normal playfield, no PMG DMA, double-line PMGs */
/* Playfield modes: */
#define DMACTL_PLAYFIELD_NONE 0x00
#define DMACTL_PLAYFIELD_NARROW 0x01 /* e.g., 32 bytes per scanline with thick borders */
#define DMACTL_PLAYFIELD_NORMAL 0x02 /* e.g., 40 bytes per scanline with normal borders */
#define DMACTL_PLAYFIELD_WIDE 0x03 /* e.g., 48 bytes per scanline with no borders (overscan) */
/* Other options: */
/* If not set, GTIA's GRAFP0 thru GRAFP3, and/or GRAFM registers are used for
** player & missile shapes, respectively. (Modify the registers during the horizontal blank
** (Display List Interrupt), a la "racing the beam" on an Atari VCS/2600, )
** if set, ANTIC's PMBASE will be used to fetch shapes from memory via DMA.
*/
#define DMACTL_DMA_MISSILES 0x04
#define DMACTL_DMA_PLAYERS 0x08
/* Unless set, PMGs (as fetched via DMA) will be double-scanline resolution */
#define DMACTL_PMG_SINGLELINE 0x10
/* Unless set, ANTIC operation is disabled, since it cannot fetch
** Display List instructions
*/
#define DMACTL_DMA_FETCH 0x20
/*****************************************************************************/
/* CHACTL register options */
/*****************************************************************************/
/* Initialized to 2 (CHACTL_CHAR_NORMAL | CHACTL_INV_PRESENT) */
/* Inverted (upside-down) characters */
#define CHACTL_CHAR_NORMAL 0x00
#define CHACTL_CHAR_INVERTED 0x04
/* Inverse (reverse-video) characters */
#define CHACTL_INV_TRANS 0x00 /* chars with high-bit shown */
#define CHACTL_INV_OPAQUE 0x01 /* chars with high-bit appear as space */
#define CHACTL_INV_PRESENT 0x02 /* chars with high-bit are reverse-video */
/*****************************************************************************/
/* Values for NMIEN (enabling interrupts) & NMIST (cause for the interrupt) */
/*****************************************************************************/
/* Display List Interrupts
** Called on a modeline when "DL_DLI" bit is set the ANTIC instruction,
** and jumps through VDSLST vector.
*/
#define NMIEN_DLI 0x80
/* Vertical Blank Interrupt
** Called during every vertical blank; see SYSVBV, VVBLKI, CRITIC, and VVBLKD,
** as well as the SETVBV routine.
*/
#define NMIEN_VBI 0x40
/* [Reset] key pressed */
#define NMIEN_RESET 0x20
/*****************************************************************************/
/* ANTIC instruction set */
/*****************************************************************************/
/* Absolute instructions (non mode lines) */
#define DL_JMP ((unsigned char) 1)
#define DL_JVB ((unsigned char) 65)
#define DL_BLK1 ((unsigned char) 0) /* 1 blank scanline */
#define DL_BLK2 ((unsigned char) 16) /* 2 blank scanlines */
#define DL_BLK3 ((unsigned char) 32) /* ...etc. */
#define DL_BLK4 ((unsigned char) 48)
#define DL_BLK5 ((unsigned char) 64)
#define DL_BLK6 ((unsigned char) 80)
#define DL_BLK7 ((unsigned char) 96)
#define DL_BLK8 ((unsigned char) 112)
/* Absolute instructions (mode lines) */
/* Note: Actual width varies (e.g., 40 vs 32 vs 48) depending on
** normal vs narrow vs wide (overscan) playfield setting; see DMACTL
*/
/* Character modes (text, tile graphics, etc.) */
/* monochrome, 40 character & 8 scanlines per mode line (aka Atari BASIC GRAPHICS 0 via OS's CIO routines) */
#define DL_CHR40x8x1 ((unsigned char) 2)
/* monochrome, 40 character & 10 scanlines per mode line (like GR. 0, with descenders) */
#define DL_CHR40x10x1 ((unsigned char) 3)
/* colour, 40 character & 8 scanlines per mode line (GR. 12) */
#define DL_CHR40x8x4 ((unsigned char) 4)
/* colour, 40 character & 16 scanlines per mode line (GR. 13) */
#define DL_CHR40x16x4 ((unsigned char) 5)
/* colour (duochrome per character), 20 character & 8 scanlines per mode line (GR. 1) */
#define DL_CHR20x8x2 ((unsigned char) 6)
/* colour (duochrome per character), 20 character & 16 scanlines per mode line (GR. 2) */
#define DL_CHR20x16x2 ((unsigned char) 7)
/* Bitmap modes */
/* colour, 40 pixel & 8 scanlines per mode line (GR. 3) */
#define DL_MAP40x8x4 ((unsigned char) 8)
/* 'duochrome', 80 pixel & 4 scanlines per mode line (GR.4) */
#define DL_MAP80x4x2 ((unsigned char) 9)
/* colour, 80 pixel & 4 scanlines per mode line (GR.5) */
#define DL_MAP80x4x4 ((unsigned char) 10)
/* 'duochrome', 160 pixel & 2 scanlines per mode line (GR.6) */
#define DL_MAP160x2x2 ((unsigned char) 11)
/* 'duochrome', 160 pixel & 1 scanline per mode line (GR.14) */
#define DL_MAP160x1x2 ((unsigned char) 12)
/* 4 colours, 160 pixel & 2 scanlines per mode line (GR.7) */
#define DL_MAP160x2x4 ((unsigned char) 13)
/* 4 colours, 160 pixel & 1 scanline per mode line (GR.15) */
#define DL_MAP160x1x4 ((unsigned char) 14)
/* monochrome, 320 pixel & 1 scanline per mode line (GR.8) */
#define DL_MAP320x1x1 ((unsigned char) 15)
/* Equivalents, for people familiar with Atari 8-bit OS */
#define DL_GRAPHICS0 DL_CHR40x8x1
#define DL_GRAPHICS1 DL_CHR20x8x2
#define DL_GRAPHICS2 DL_CHR20x16x2
#define DL_GRAPHICS3 DL_MAP40x8x4
#define DL_GRAPHICS4 DL_MAP80x4x2
#define DL_GRAPHICS5 DL_MAP80x4x4
#define DL_GRAPHICS6 DL_MAP160x2x2
#define DL_GRAPHICS7 DL_MAP160x2x4
#define DL_GRAPHICS8 DL_MAP320x1x1
#define DL_GRAPHICS9 DL_MAP320x1x1 /* N.B.: GRAPHICS 9, 10, and 11 also involve GTIA's PRIOR register */
#define DL_GRAPHICS10 DL_MAP320x1x1
#define DL_GRAPHICS11 DL_MAP320x1x1
#define DL_GRAPHICS12 DL_CHR40x8x4 /* N.B.: Atari 400/800 OS didn't have GRAPHICS 12 or 13 */
#define DL_GRAPHICS13 DL_CHR40x16x4
#define DL_GRAPHICS14 DL_MAP160x1x2
#define DL_GRAPHICS15 DL_MAP160x1x4
/* Atari 400/800 OS didn't have GRAPHICS 14 or 15, so they were known by "6+" and "7+" */
#define DL_GRAPHICS6PLUS DL_GRAPHICS14
#define DL_GRAPHICS7PLUS DL_GRAPHICS15
/* Neither Atari 400/800 nor XL OS supported 10-scanline (descenders) text mode via CIO */
#define DL_GRAPHICS0_DESCENDERS DL_CHR40x10x1
/* Modifiers to mode lines */
#define DL_HSCROL(x) ((unsigned char)((x) | 16)) /* enable smooth horizontal scrolling on this line; see HSCROL */
#define DL_VSCROL(x) ((unsigned char)((x) | 32)) /* enable smooth vertical scrolling on this line; see VSCROL */
#define DL_LMS(x) ((unsigned char)((x) | 64)) /* Load Memory Scan (next two bytes must be the LSB/MSB of the data to load) */
/* General modifier */
#define DL_DLI(x) ((unsigned char)((x) | 128)) /* enable Display List Interrupt on this mode line */
/* End of _antic.h */
#endif /* #ifndef __ANTIC_H */