/* Internal include file, do not use directly */
/* */
/* */
+/* "ANTIC 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 sprites 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" */
/* */
/* (C) 2000 Freddy Offenga <taf_offenga@yahoo.com> */
/* 24-Jan-2011: Christian Krueger: Added defines for Antic instruction set */
+/* 2019-01-12: Bill Kendrick <nbs@sonic.net>: More defines for registers */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
#ifndef __ANTIC_H
#define __ANTIC_H
-/* Define a structure with the antic register offsets */
+/* Define a structure with the ANTIC coprocessor's register offsets */
struct __antic {
- unsigned char dmactl; /* direct memory access control */
- unsigned char chactl; /* character mode control */
+ unsigned char dmactl; /* (W) direct memory access control */
+
+/* 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: */
+#define DMACTL_DMA_MISSILES 0x04 /* if not set, GTIA's GRAFP0 thru GRAFP3 used for player shapes; if set, ANTIC's PMBASE will be used to fetch shapes via DMA */
+#define DMACTL_DMA_PLAYERS 0x08 /* (ditto, using GTIA's GRAFM for missile shapes...) */
+#define DMACTL_PMG_SINGLELINE 0x10 /* if not set, default is double-scanline resolution PMGs */
+#define DMACTL_DMA_FETCH 0x20 /* if not set, disables ANTIC operation since it cannot fetch Display List instructions */
+/* Initialized to 0x22 (DMA fetch, normal playfield, no PMG DMA, double-line PMGs) */
+
+
+ unsigned char chactl; /* (W) character mode control */
+
+/* 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 */
+/* N.B. Default is "CHACTL_CHAR_NORMAL | CHACTL_INV_PRESENT", aka decimal 2 */
+
+
unsigned char dlistl; /* display list pointer low-byte */
unsigned char dlisth; /* display list pointer high-byte */
- unsigned char hscrol; /* horizontal scroll enable */
- unsigned char vscrol; /* vertical scroll enable */
+ unsigned char hscrol; /* (W) horizontal scroll enable */
+ unsigned char vscrol; /* (W) vertical scroll enable */
unsigned char unuse0; /* unused */
- unsigned char pmbase; /* msb of p/m base address */
+ 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; /* character base address */
- unsigned char wsync; /* wait for horizontal synchronization */
- unsigned char vcount; /* vertical line counter */
- unsigned char penh; /* light pen horizontal position */
- unsigned char penv; /* light pen vertical position */
- unsigned char nmien; /* non-maskable interrupt enable */
- unsigned char nmires; /* nmi reset/status */
+ unsigned char chbase; /* (W) 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 */
+
+/* NMIEN settings: */
+#define NMIEN_DLI 0x80 /* see also: DL_DLI */
+#define NMIEN_VBI 0x40
+#define NMIEN_RESET 0x20
+
+ unsigned char nmires; /* (W) ("NMIRES") nmi reset; (R) ("NMIST") nmi status */
};
-/* antic instruction set */
+/* ANTIC instruction set */
-/* absolute instructions (non mode lines) */
+/* Absolute instructions (non mode lines) */
#define DL_JMP ((unsigned char) 1)
#define DL_JVB ((unsigned char) 65)
-#define DL_BLK1 ((unsigned char) 0)
-#define DL_BLK2 ((unsigned char) 16)
-#define DL_BLK3 ((unsigned char) 32)
+#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) */
-#define DL_CHR40x8x1 ((unsigned char) 2) /* monochrome, 40 character & 8 scanlines per mode line (GR. 0) */
-#define DL_CHR40x10x1 ((unsigned char) 3) /* monochrome, 40 character & 10 scanlines per mode line */
+/* 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.) */
+#define DL_CHR40x8x1 ((unsigned char) 2) /* monochrome, 40 character & 8 scanlines per mode line (aka Atari BASIC GRAPHICS 0 via OS's CIO routines) */
+#define DL_CHR40x10x1 ((unsigned char) 3) /* monochrome, 40 character & 10 scanlines per mode line (like GR. 0, with descenders) */
#define DL_CHR40x8x4 ((unsigned char) 4) /* colour, 40 character & 8 scanlines per mode line (GR. 12) */
#define DL_CHR40x16x4 ((unsigned char) 5) /* colour, 40 character & 16 scanlines per mode line (GR. 13) */
#define DL_CHR20x8x2 ((unsigned char) 6) /* colour (duochrome per character), 20 character & 8 scanlines per mode line (GR. 1) */
#define DL_CHR20x16x2 ((unsigned char) 7) /* colour (duochrome per character), 20 character & 16 scanlines per mode line (GR. 2) */
+/* Bitmap modes */
#define DL_MAP40x8x4 ((unsigned char) 8) /* colour, 40 pixel & 8 scanlines per mode line (GR. 3) */
#define DL_MAP80x4x2 ((unsigned char) 9) /* 'duochrome', 80 pixel & 4 scanlines per mode line (GR.4) */
#define DL_MAP80x4x4 ((unsigned char) 10) /* colour, 80 pixel & 4 scanlines per mode line (GR.5) */
#define DL_MAP160x1x4 ((unsigned char) 14) /* 4 colours, 160 pixel & 1 scanline per mode line (GR.15) */
#define DL_MAP320x1x1 ((unsigned char) 15) /* monochrome, 320 pixel & 1 scanline per mode line (GR.8) */
-/* modifiers on mode lines */
-#define DL_HSCROL(x) ((unsigned char)((x) | 16))
-#define DL_VSCROL(x) ((unsigned char)((x) | 32))
-#define DL_LMS(x) ((unsigned char)((x) | 64))
+/* 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; requires NMIEN set to enable DLIs */
+
-/* general modifier */
-#define DL_DLI(x) ((unsigned char)((x) | 128))
+/* Macros for the beginning and end of functions used as Display List Interrupts */
+#define DLI_START asm("pha"); asm("txa"); asm("pha"); asm("tya"); asm("pha");
+#define DLI_END asm("pla"); asm("tay"); asm("pla"); asm("tax"); asm("pla"); asm("rti");
/* End of _antic.h */
#endif /* #ifndef __ANTIC_H */
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