Genesis-Plus-GX/source/m68k/m68k.h

250 lines
9.5 KiB
C

#ifndef M68K__HEADER
#define M68K__HEADER
/* ======================================================================== */
/* ========================= LICENSING & COPYRIGHT ======================== */
/* ======================================================================== */
/*
* MUSASHI
* Version 3.32
*
* A portable Motorola M680x0 processor emulation engine.
* Copyright Karl Stenerud. All rights reserved.
*
* This code may be freely used for non-commercial purposes as long as this
* copyright notice remains unaltered in the source code and any binary files
* containing this code in compiled form.
*
* All other licensing terms must be negotiated with the author
* (Karl Stenerud).
*
* The latest version of this code can be obtained at:
* http://kstenerud.cjb.net
*/
/* Modified by Eke-Eke for Genesis Plus GX:
- removed unused stuff to reduce memory usage / optimize execution (multiple CPU types support, NMI support, ...)
- moved stuff to compile statically in a single object file
- implemented support for global cycle count (shared by 68k & Z80 CPU)
- added support for interrupt latency (Sesame's Street Counting Cafe, Fatal Rewind)
- added proper cycle use on reset
- added cycle accurate timings for MUL/DIV instructions (thanks to Jorge Cwik !)
- fixed undocumented flags for DIV instructions (Blood Shot)
*/
/* ======================================================================== */
/* ============================= CONFIGURATION ============================ */
/* ======================================================================== */
/* Import the configuration for this build */
#include "m68kconf.h"
/* ======================================================================== */
/* ============================ GENERAL DEFINES =========================== */
/* ======================================================================== */
/* There are 7 levels of interrupt to the 68K.
* A transition from < 7 to 7 will cause a non-maskable interrupt (NMI).
*/
#define M68K_IRQ_NONE 0
#define M68K_IRQ_1 1
#define M68K_IRQ_2 2
#define M68K_IRQ_3 3
#define M68K_IRQ_4 4
#define M68K_IRQ_5 5
#define M68K_IRQ_6 6
#define M68K_IRQ_7 7
/* Special interrupt acknowledge values.
* Use these as special returns from the interrupt acknowledge callback
* (specified later in this header).
*/
/* Causes an interrupt autovector (0x18 + interrupt level) to be taken.
* This happens in a real 68K if VPA or AVEC is asserted during an interrupt
* acknowledge cycle instead of DTACK.
*/
#define M68K_INT_ACK_AUTOVECTOR 0xffffffff
/* Causes the spurious interrupt vector (0x18) to be taken
* This happens in a real 68K if BERR is asserted during the interrupt
* acknowledge cycle (i.e. no devices responded to the acknowledge).
*/
#define M68K_INT_ACK_SPURIOUS 0xfffffffe
/* Registers used by m68k_get_reg() and m68k_set_reg() */
typedef enum
{
/* Real registers */
M68K_REG_D0, /* Data registers */
M68K_REG_D1,
M68K_REG_D2,
M68K_REG_D3,
M68K_REG_D4,
M68K_REG_D5,
M68K_REG_D6,
M68K_REG_D7,
M68K_REG_A0, /* Address registers */
M68K_REG_A1,
M68K_REG_A2,
M68K_REG_A3,
M68K_REG_A4,
M68K_REG_A5,
M68K_REG_A6,
M68K_REG_A7,
M68K_REG_PC, /* Program Counter */
M68K_REG_SR, /* Status Register */
M68K_REG_SP, /* The current Stack Pointer (located in A7) */
M68K_REG_USP, /* User Stack Pointer */
M68K_REG_ISP, /* Interrupt Stack Pointer */
#if M68K_EMULATE_PREFETCH
/* Assumed registers */
/* These are cheat registers which emulate the 1-longword prefetch
* present in the 68000 and 68010.
*/
M68K_REG_PREF_ADDR, /* Last prefetch address */
M68K_REG_PREF_DATA, /* Last prefetch data */
#endif
/* Convenience registers */
M68K_REG_IR /* Instruction register */
} m68k_register_t;
/* ======================================================================== */
/* ====================== FUNCTIONS CALLED BY THE CPU ===================== */
/* ======================================================================== */
#include "macros.h"
/* 68k memory map structure */
typedef struct
{
unsigned char *base; /* direct memory access (ROM, RAM) */
unsigned int (*read8)(unsigned int address); /* I/O byte read access */
unsigned int (*read16)(unsigned int address); /* I/O word read access */
void (*write8)(unsigned int address, unsigned int data); /* I/O byte write access */
void (*write16)(unsigned int address, unsigned int data); /* I/O word write access */
} _m68k_memory_map;
/* 68k memory map */
_m68k_memory_map m68k_memory_map[256];
/* Read data immediately following the PC */
#define m68k_read_immediate_16(address) *(uint16 *)(m68k_memory_map[((address)>>16)&0xff].base + ((address) & 0xffff))
#define m68k_read_immediate_32(address) (m68k_read_immediate_16(address) << 16) | (m68k_read_immediate_16(address+2))
/* Read data relative to the PC */
#define m68k_read_pcrelative_8(address) READ_BYTE(m68k_memory_map[((address)>>16)&0xff].base, (address) & 0xffff)
#define m68k_read_pcrelative_16(address) m68k_read_immediate_16(address)
#define m68k_read_pcrelative_32(address) m68k_read_immediate_32(address)
/* ======================================================================== */
/* ============================== CALLBACKS =============================== */
/* ======================================================================== */
/* These functions allow you to set callbacks to the host when specific events
* occur. Note that you must enable the corresponding value in m68kconf.h
* in order for these to do anything useful.
* Note: I have defined default callbacks which are used if you have enabled
* the corresponding #define in m68kconf.h but either haven't assigned a
* callback or have assigned a callback of NULL.
*/
#if M68K_EMULATE_INT_ACK == OPT_ON
/* Set the callback for an interrupt acknowledge.
* You must enable M68K_EMULATE_INT_ACK in m68kconf.h.
* The CPU will call the callback with the interrupt level being acknowledged.
* The host program must return either a vector from 0x02-0xff, or one of the
* special interrupt acknowledge values specified earlier in this header.
* If this is not implemented, the CPU will always assume an autovectored
* interrupt, and will automatically clear the interrupt request when it
* services the interrupt.
* Default behavior: return M68K_INT_ACK_AUTOVECTOR.
*/
void m68k_set_int_ack_callback(int (*callback)(int int_level));
#endif
#if M68K_EMULATE_RESET == OPT_ON
/* Set the callback for the RESET instruction.
* You must enable M68K_EMULATE_RESET in m68kconf.h.
* The CPU calls this callback every time it encounters a RESET instruction.
* Default behavior: do nothing.
*/
void m68k_set_reset_instr_callback(void (*callback)(void));
#endif
#if M68K_TAS_HAS_CALLBACK == OPT_ON
/* Set the callback for the TAS instruction.
* You must enable M68K_TAS_HAS_CALLBACK in m68kconf.h.
* The CPU calls this callback every time it encounters a TAS instruction.
* Default behavior: return 1, allow writeback.
*/
void m68k_set_tas_instr_callback(int (*callback)(void));
#endif
#if M68K_EMULATE_FC == OPT_ON
/* Set the callback for CPU function code changes.
* You must enable M68K_EMULATE_FC in m68kconf.h.
* The CPU calls this callback with the function code before every memory
* access to set the CPU's function code according to what kind of memory
* access it is (supervisor/user, program/data and such).
* Default behavior: do nothing.
*/
void m68k_set_fc_callback(void (*callback)(unsigned int new_fc));
#endif
/* ======================================================================== */
/* ====================== FUNCTIONS TO ACCESS THE CPU ===================== */
/* ======================================================================== */
/* Do whatever initialisations the core requires. Should be called
* at least once at init time.
*/
extern void m68k_init(void);
/* Pulse the RESET pin on the CPU.
* You *MUST* reset the CPU at least once to initialize the emulation
*/
extern void m68k_pulse_reset(void);
/* Run until given cycle count is reached */
extern void m68k_run(unsigned int cycles);
/* Set the IPL0-IPL2 pins on the CPU (IRQ).
* A transition from < 7 to 7 will cause a non-maskable interrupt (NMI).
* Setting IRQ to 0 will clear an interrupt request.
*/
extern void m68k_update_irq(unsigned int mask);
extern void m68k_set_irq(unsigned int int_level);
extern void m68k_set_irq_delay(unsigned int int_level);
/* Halt the CPU as if you pulsed the HALT pin. */
extern void m68k_pulse_halt(void);
/* Peek at the internals of a CPU context. This can either be a context
* retrieved using m68k_get_context() or the currently running context.
* If context is NULL, the currently running CPU context will be used.
*/
extern unsigned int m68k_get_reg(m68k_register_t reg);
/* Poke values into the internals of the currently running CPU context */
extern void m68k_set_reg(m68k_register_t reg, unsigned int value);
/* ======================================================================== */
/* ============================== END OF FILE ============================= */
/* ======================================================================== */
#endif /* M68K__HEADER */