core/retro_control.h at 7c83b415d7cc · doomsdayone/retro-remote-debug-controller

# 7c83b415d7cc retro-remote-debug-controller / core / retro_control.h

5.3 KiB · Objective-C · last changed core: guard the public header with extern "C" for C++ consumers 3 months ago source blame history raw

/* retro_control.h — portable emulator control server (see ../SPEC.md).
 *
 * A retro-platform emulator implements the small read-only backend below and
 * calls retro_control_start(). The shared server (retro_control.c) owns the
 * socket loop, HTTP parsing, PPM/JSON encoding, and control flow
 * (pause / step / free-run). It always binds 127.0.0.1. Contract 0.1.0.
 *
 * Integration is three calls in the emulator's main loop:
 *   retro_control_service();                 // once per iteration (cheap)
 *   if (!retro_control_running()) { idle; }  // gate advancing the machine
 *   ... run one instruction / frame ...
 *   if (frame_completed) retro_control_on_frame();
 *
 * Threading: the server runs on its own thread but never touches machine state
 * there. State-reading endpoints (/mem, /regs, /screenshot) are executed inside
 * retro_control_service() ON THE EMULATOR THREAD, so every read is consistent.
 * The backend callbacks are therefore called from the emulator thread (except
 * get_frame_count, which the server may also read for /status — make it a plain
 * atomic-ish counter read).
 */
#ifndef RETRO_CONTROL_H
#define RETRO_CONTROL_H

#include <stdint.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Highest contract the core implements. The server advertises the highest level
 * whose backend callbacks are all present: 0.3.0 needs inject_key + write_mem +
 * capture_audio; 0.2.0 needs inject_key; else 0.1.0. Keeps a partial backend
 * honest. */
#define RETRO_CONTROL_CONTRACT "0.3.0"

/* Native framebuffer pixel layout; the server swizzles to PPM RGB. */
typedef enum {
    RETRO_PIX_RGB888 = 0,   /* 3 bytes/px: R,G,B                       */
    RETRO_PIX_RGBA8888,     /* 4 bytes/px: R,G,B,A                     */
    RETRO_PIX_BGRA8888      /* 4 bytes/px: B,G,R,A (x16 framebuffer)   */
} retro_pix_fmt_t;

typedef struct {
    const uint8_t *pixels;  /* start of the current complete frame     */
    int width;
    int height;
    retro_pix_fmt_t fmt;
} retro_framebuffer_t;

/* Key action for inject_key (0.2). */
typedef enum {
    RETRO_KEY_TAP  = 0,   /* press then release */
    RETRO_KEY_DOWN = 1,   /* press / hold       */
    RETRO_KEY_UP   = 2    /* release            */
} retro_key_action_t;

/* The emulator implements these. Any may be NULL: the matching endpoint then
 * returns 501 Not Implemented. */
typedef struct retro_control_backend {
    const char *platform;   /* "x16" | "neo6502" | "agon" | ...        */
    const char *emulator;   /* human name, e.g. "x16emu"               */

    /* Debug-read up to min(len, out_cap) bytes at addr into out, side-effect
     * free. bank is the optional bank selector (<0 = current bank). Returns the
     * number of bytes written. */
    uint32_t (*read_mem)(uint32_t addr, int32_t bank, uint32_t len,
                         uint8_t *out, uint32_t out_cap);

    /* Write a JSON object of registers into buf (NUL-terminated). */
    void (*get_regs_json)(char *buf, size_t cap);

    /* Report the current complete-frame framebuffer. */
    void (*get_framebuffer)(retro_framebuffer_t *out);

    /* Monotonic completed-frame counter. */
    uint64_t (*get_frame_count)(void);

    /* 0.2: inject a key. is_text=1 => `value` is a character code point;
     * is_text=0 => `value` is a raw platform key code. `action` is a
     * retro_key_action_t. Return 1 on success, 0 if unmappable (server -> 400).
     * NULL => /key returns 501 and the server advertises contract 0.1.0. */
    int (*inject_key)(int is_text, uint32_t value, int action);

    /* 0.2: soft/cold reset the machine. NULL => /reset returns 501. */
    void (*reset)(void);

    /* 0.3: write len bytes from `in` at addr (debug/state poke; bank<0 =
     * current). Intended for RAM/state — I/O-register writes may trigger device
     * side effects. Return bytes written. NULL => POST /mem returns 501. */
    uint32_t (*write_mem)(uint32_t addr, int32_t bank, uint32_t len,
                          const uint8_t *in);

    /* 0.3: drain up to `cap` interleaved signed-16-bit audio samples the
     * emulator has synthesised since the last call into `out`; set *rate and
     * *channels; set *dropped to samples lost to overflow since the last drain.
     * Return the number of int16 samples written. NULL => /audio returns 501. */
    uint32_t (*capture_audio)(int16_t *out, uint32_t cap,
                              int *rate, int *channels, uint32_t *dropped);
} retro_control_backend_t;

/* Start the server thread bound to 127.0.0.1:port. Non-blocking; 0 on success,
 * negative on error. backend must outlive the server. */
int  retro_control_start(int port, const retro_control_backend_t *backend);

/* Drain a pending control request. Call once per main-loop iteration, at an
 * instruction/frame boundary. Cheap no-op when idle and when control is off. */
void retro_control_service(void);

/* Nonzero => the machine should advance this iteration. Returns 1 always when
 * control is off or the machine is free-running; 0 when paused with no steps
 * left. */
int  retro_control_running(void);

/* Call when a video frame completes. Drives /step (decrements the step budget,
 * halts and answers when it reaches zero). No-op when control is off. */
void retro_control_on_frame(void);

/* Stop the server (optional; process exit is fine too). */
void retro_control_stop(void);

#ifdef __cplusplus
}
#endif

#endif /* RETRO_CONTROL_H */

961b3c61 Andy McCall 3 months ago	1	/* retro_control.h — portable emulator control server (see ../SPEC.md).
	2	*
	3	* A retro-platform emulator implements the small read-only backend below and
	4	* calls retro_control_start(). The shared server (retro_control.c) owns the
	5	* socket loop, HTTP parsing, PPM/JSON encoding, and control flow
	6	* (pause / step / free-run). It always binds 127.0.0.1. Contract 0.1.0.
	7	*
	8	* Integration is three calls in the emulator's main loop:
	9	* retro_control_service(); // once per iteration (cheap)
	10	* if (!retro_control_running()) { idle; } // gate advancing the machine
	11	* ... run one instruction / frame ...
	12	* if (frame_completed) retro_control_on_frame();
	13	*
	14	* Threading: the server runs on its own thread but never touches machine state
	15	* there. State-reading endpoints (/mem, /regs, /screenshot) are executed inside
	16	* retro_control_service() ON THE EMULATOR THREAD, so every read is consistent.
	17	* The backend callbacks are therefore called from the emulator thread (except
	18	* get_frame_count, which the server may also read for /status — make it a plain
	19	* atomic-ish counter read).
	20	*/
	21	#ifndef RETRO_CONTROL_H
	22	#define RETRO_CONTROL_H
	23
	24	#include <stdint.h>
	25	#include <stddef.h>
	26
7c83b415 Andy McCall 3 months ago ↶	27	#ifdef __cplusplus
	28	extern "C" {
	29	#endif
	30
674b8447 Andy McCall 3 months ago ↶	31	/* Highest contract the core implements. The server advertises the highest level
	32	* whose backend callbacks are all present: 0.3.0 needs inject_key + write_mem +
	33	* capture_audio; 0.2.0 needs inject_key; else 0.1.0. Keeps a partial backend
	34	* honest. */
	35	#define RETRO_CONTROL_CONTRACT "0.3.0"
961b3c61 Andy McCall 3 months ago	36
	37	/* Native framebuffer pixel layout; the server swizzles to PPM RGB. */
	38	typedef enum {
	39	RETRO_PIX_RGB888 = 0, /* 3 bytes/px: R,G,B */
	40	RETRO_PIX_RGBA8888, /* 4 bytes/px: R,G,B,A */
	41	RETRO_PIX_BGRA8888 /* 4 bytes/px: B,G,R,A (x16 framebuffer) */
	42	} retro_pix_fmt_t;
	43
	44	typedef struct {
	45	const uint8_t pixels; / start of the current complete frame */
	46	int width;
	47	int height;
	48	retro_pix_fmt_t fmt;
	49	} retro_framebuffer_t;
	50
689a9ccb Andy McCall 3 months ago ↶	51	/* Key action for inject_key (0.2). */
	52	typedef enum {
	53	RETRO_KEY_TAP = 0, /* press then release */
	54	RETRO_KEY_DOWN = 1, /* press / hold */
	55	RETRO_KEY_UP = 2 /* release */
	56	} retro_key_action_t;
	57
961b3c61 Andy McCall 3 months ago	58	/* The emulator implements these. Any may be NULL: the matching endpoint then
	59	* returns 501 Not Implemented. */
	60	typedef struct retro_control_backend {
	61	const char platform; / "x16" \| "neo6502" \| "agon" \| ... */
	62	const char emulator; / human name, e.g. "x16emu" */
	63
	64	/* Debug-read up to min(len, out_cap) bytes at addr into out, side-effect
	65	* free. bank is the optional bank selector (<0 = current bank). Returns the
	66	* number of bytes written. */
	67	uint32_t (*read_mem)(uint32_t addr, int32_t bank, uint32_t len,
	68	uint8_t *out, uint32_t out_cap);
	69
	70	/* Write a JSON object of registers into buf (NUL-terminated). */
	71	void (get_regs_json)(char buf, size_t cap);
	72
	73	/* Report the current complete-frame framebuffer. */
	74	void (get_framebuffer)(retro_framebuffer_t out);
	75
	76	/* Monotonic completed-frame counter. */
	77	uint64_t (*get_frame_count)(void);
689a9ccb Andy McCall 3 months ago ↶	78
	79	/* 0.2: inject a key. is_text=1 => `value` is a character code point;
	80	* is_text=0 => `value` is a raw platform key code. `action` is a
	81	* retro_key_action_t. Return 1 on success, 0 if unmappable (server -> 400).
	82	* NULL => /key returns 501 and the server advertises contract 0.1.0. */
	83	int (*inject_key)(int is_text, uint32_t value, int action);
	84
	85	/* 0.2: soft/cold reset the machine. NULL => /reset returns 501. */
	86	void (*reset)(void);
674b8447 Andy McCall 3 months ago ↶	87
	88	/* 0.3: write len bytes from `in` at addr (debug/state poke; bank<0 =
	89	* current). Intended for RAM/state — I/O-register writes may trigger device
	90	* side effects. Return bytes written. NULL => POST /mem returns 501. */
	91	uint32_t (*write_mem)(uint32_t addr, int32_t bank, uint32_t len,
	92	const uint8_t *in);
	93
	94	/* 0.3: drain up to `cap` interleaved signed-16-bit audio samples the
	95	* emulator has synthesised since the last call into `out`; set *rate and
	96	* channels; set dropped to samples lost to overflow since the last drain.
	97	* Return the number of int16 samples written. NULL => /audio returns 501. */
	98	uint32_t (capture_audio)(int16_t out, uint32_t cap,
	99	int rate, int channels, uint32_t *dropped);
961b3c61 Andy McCall 3 months ago	100	} retro_control_backend_t;
	101
	102	/* Start the server thread bound to 127.0.0.1:port. Non-blocking; 0 on success,
	103	* negative on error. backend must outlive the server. */
	104	int retro_control_start(int port, const retro_control_backend_t *backend);
	105
	106	/* Drain a pending control request. Call once per main-loop iteration, at an
	107	* instruction/frame boundary. Cheap no-op when idle and when control is off. */
	108	void retro_control_service(void);
	109
	110	/* Nonzero => the machine should advance this iteration. Returns 1 always when
	111	* control is off or the machine is free-running; 0 when paused with no steps
	112	* left. */
	113	int retro_control_running(void);
	114
	115	/* Call when a video frame completes. Drives /step (decrements the step budget,
	116	* halts and answers when it reaches zero). No-op when control is off. */
	117	void retro_control_on_frame(void);
	118
	119	/* Stop the server (optional; process exit is fine too). */
	120	void retro_control_stop(void);
7c83b415 Andy McCall 3 months ago ↶	121
	122	#ifdef __cplusplus
	123	}
	124	#endif
961b3c61 Andy McCall 3 months ago	125
961b3c61 Andy McCall 3 months ago	126	#endif /* RETRO_CONTROL_H */

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