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Relocate register values outside structs, + more

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Relocated register #define'd values outside of the structs,
improved comment format, expanded & corrected some things.

h/t Trevin Beattie (https://user.xmission.com/~trevin/) for the PIA
register descriptions.
This commit is contained in:
Bill Kendrick
2019-01-15 01:24:12 -08:00
parent d52af69d69
commit 4b61c54092
5 changed files with 385 additions and 163 deletions
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84
include/_antic.h
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@@ -18,7 +18,7 @@
/* */
/* (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 */
/* 2019-01-14: Bill Kendrick <nbs@sonic.net>: More defines for registers */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
@@ -47,21 +47,57 @@
/* 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 */
unsigned char nmires;
/* (W) ("NMIRES") nmi reset -- clears the interrupt request register; resets all of the NMI status together
** (R) ("NMIST") nmi status -- holds cause for the NMI interrupt
*/
};
/* 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: */
#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) */
/* 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
unsigned char chactl; /* (W) character mode control */
/* CHACTL register options */
/* Initialized to 2 (CHACTL_CHAR_NORMAL | CHACTL_INV_PRESENT) */
/* Inverted (upside-down) characters */
#define CHACTL_CHAR_NORMAL 0x00
@@ -72,31 +108,25 @@ struct __antic {
#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 */
/* Register bits for NMIEN (enabling interrupts)
** and NMIST (determining the cause for the NMI interrupt)
*/
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) 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 */
#define NMIEN_DLI 0x80
/* Display List Interrupts
** Called on a modeline when "DL_DLI" bit is set the ANTIC instruction,
** and jumps through VDSLST vector.
*/
unsigned char nmien; /* (W) non-maskable interrupt enable */
#define NMIEN_VBI 0x40
/* Vertical Blank Interrupt
** Called during every vertical blank; see SYSVBV, VVBLKI, CRITIC, and VVBLKD,
** as well as the SETVBV routine.
*/
/* 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 */
};
/* [Reset] key pressed */
/* ANTIC instruction set */