8 /* ======================================================================== */
9 /* ========================= LICENSING & COPYRIGHT ======================== */
10 /* ======================================================================== */
15 * A portable Motorola M680x0 processor emulation engine.
16 * Copyright 1998-2001 Karl Stenerud. All rights reserved.
18 * This code may be freely used for non-commercial purposes as long as this
19 * copyright notice remains unaltered in the source code and any binary files
20 * containing this code in compiled form.
22 * All other lisencing terms must be negotiated with the author
25 * The latest version of this code can be obtained at:
26 * http://kstenerud.cjb.net
29 // NOTE: The 3.3.1 release is marked as 3.3 in this file. Changed by JLH
30 // in order to clarify which version we're using...
32 /* ======================================================================== */
33 /* ============================ GENERAL DEFINES =========================== */
35 /* ======================================================================== */
37 /* There are 7 levels of interrupt to the 68K.
38 * A transition from < 7 to 7 will cause a non-maskable interrupt (NMI).
40 #define M68K_IRQ_NONE 0
50 /* Special interrupt acknowledge values.
51 * Use these as special returns from the interrupt acknowledge callback
52 * (specified later in this header).
55 /* Causes an interrupt autovector (0x18 + interrupt level) to be taken.
56 * This happens in a real 68K if VPA or AVEC is asserted during an interrupt
57 * acknowledge cycle instead of DTACK.
59 #define M68K_INT_ACK_AUTOVECTOR 0xffffffff
61 /* Causes the spurious interrupt vector (0x18) to be taken
62 * This happens in a real 68K if BERR is asserted during the interrupt
63 * acknowledge cycle (i.e. no devices responded to the acknowledge).
65 #define M68K_INT_ACK_SPURIOUS 0xfffffffe
68 /* CPU types for use in m68k_set_cpu_type() */
71 M68K_CPU_TYPE_INVALID,
74 M68K_CPU_TYPE_68EC020,
76 M68K_CPU_TYPE_68030, /* Supported by disassembler ONLY */
77 M68K_CPU_TYPE_68040 /* Supported by disassembler ONLY */
80 /* Registers used by m68k_get_reg() and m68k_set_reg() */
84 M68K_REG_D0, /* Data registers */
92 M68K_REG_A0, /* Address registers */
100 M68K_REG_PC, /* Program Counter */
101 M68K_REG_SR, /* Status Register */
102 M68K_REG_SP, /* The current Stack Pointer (located in A7) */
103 M68K_REG_USP, /* User Stack Pointer */
104 M68K_REG_ISP, /* Interrupt Stack Pointer */
105 M68K_REG_MSP, /* Master Stack Pointer */
106 M68K_REG_SFC, /* Source Function Code */
107 M68K_REG_DFC, /* Destination Function Code */
108 M68K_REG_VBR, /* Vector Base Register */
109 M68K_REG_CACR, /* Cache Control Register */
110 M68K_REG_CAAR, /* Cache Address Register */
112 /* Assumed registers */
113 /* These are cheat registers which emulate the 1-longword prefetch
114 * present in the 68000 and 68010.
116 M68K_REG_PREF_ADDR, /* Last prefetch address */
117 M68K_REG_PREF_DATA, /* Last prefetch data */
119 /* Convenience registers */
120 M68K_REG_PPC, /* Previous value in the program counter */
121 M68K_REG_IR, /* Instruction register */
122 M68K_REG_CPU_TYPE /* Type of CPU being run */
125 /* ======================================================================== */
126 /* ====================== FUNCTIONS CALLED BY THE CPU ===================== */
127 /* ======================================================================== */
129 /* You will have to implement these functions */
131 /* read/write functions called by the CPU to access memory.
132 * while values used are 32 bits, only the appropriate number
133 * of bits are relevant (i.e. in write_memory_8, only the lower 8 bits
134 * of value should be written to memory).
136 * NOTE: I have separated the immediate and PC-relative memory fetches
137 * from the other memory fetches because some systems require
138 * differentiation between PROGRAM and DATA fetches (usually
139 * for security setups such as encryption).
140 * This separation can either be achieved by setting
141 * M68K_SEPARATE_READS in m68kconf.h and defining
142 * the read functions, or by setting M68K_EMULATE_FC and
143 * making a function code callback function.
144 * Using the callback offers better emulation coverage
145 * because you can also monitor whether the CPU is in SYSTEM or
146 * USER mode, but it is also slower.
149 /* Read from anywhere */
150 unsigned int m68k_read_memory_8(unsigned int address);
151 unsigned int m68k_read_memory_16(unsigned int address);
152 unsigned int m68k_read_memory_32(unsigned int address);
154 /* Read data immediately following the PC */
155 unsigned int m68k_read_immediate_16(unsigned int address);
156 unsigned int m68k_read_immediate_32(unsigned int address);
158 /* Read data relative to the PC */
159 unsigned int m68k_read_pcrelative_8(unsigned int address);
160 unsigned int m68k_read_pcrelative_16(unsigned int address);
161 unsigned int m68k_read_pcrelative_32(unsigned int address);
163 /* Memory access for the disassembler */
164 unsigned int m68k_read_disassembler_8 (unsigned int address);
165 unsigned int m68k_read_disassembler_16 (unsigned int address);
166 unsigned int m68k_read_disassembler_32 (unsigned int address);
168 /* Write to anywhere */
169 void m68k_write_memory_8(unsigned int address, unsigned int value);
170 void m68k_write_memory_16(unsigned int address, unsigned int value);
171 void m68k_write_memory_32(unsigned int address, unsigned int value);
175 /* ======================================================================== */
176 /* ============================== CALLBACKS =============================== */
177 /* ======================================================================== */
179 /* These functions allow you to set callbacks to the host when specific events
180 * occur. Note that you must enable the corresponding value in m68kconf.h
181 * in order for these to do anything useful.
182 * Note: I have defined default callbacks which are used if you have enabled
183 * the corresponding #define in m68kconf.h but either haven't assigned a
184 * callback or have assigned a callback of NULL.
187 /* Set the callback for an interrupt acknowledge.
188 * You must enable M68K_EMULATE_INT_ACK in m68kconf.h.
189 * The CPU will call the callback with the interrupt level being acknowledged.
190 * The host program must return either a vector from 0x02-0xff, or one of the
191 * special interrupt acknowledge values specified earlier in this header.
192 * If this is not implemented, the CPU will always assume an autovectored
193 * interrupt, and will automatically clear the interrupt request when it
194 * services the interrupt.
195 * Default behavior: return M68K_INT_ACK_AUTOVECTOR.
197 void m68k_set_int_ack_callback(int (*callback)(int int_level));
200 /* Set the callback for a breakpoint acknowledge (68010+).
201 * You must enable M68K_EMULATE_BKPT_ACK in m68kconf.h.
202 * The CPU will call the callback with whatever was in the data field of the
203 * BKPT instruction for 68020+, or 0 for 68010.
204 * Default behavior: do nothing.
206 void m68k_set_bkpt_ack_callback(void (*callback)(unsigned int data));
209 /* Set the callback for the RESET instruction.
210 * You must enable M68K_EMULATE_RESET in m68kconf.h.
211 * The CPU calls this callback every time it encounters a RESET instruction.
212 * Default behavior: do nothing.
214 void m68k_set_reset_instr_callback(void (*callback)(void));
217 /* Set the callback for informing of a large PC change.
218 * You must enable M68K_MONITOR_PC in m68kconf.h.
219 * The CPU calls this callback with the new PC value every time the PC changes
220 * by a large value (currently set for changes by longwords).
221 * Default behavior: do nothing.
223 void m68k_set_pc_changed_callback(void (*callback)(unsigned int new_pc));
226 /* Set the callback for CPU function code changes.
227 * You must enable M68K_EMULATE_FC in m68kconf.h.
228 * The CPU calls this callback with the function code before every memory
229 * access to set the CPU's function code according to what kind of memory
230 * access it is (supervisor/user, program/data and such).
231 * Default behavior: do nothing.
233 void m68k_set_fc_callback(void (*callback)(unsigned int new_fc));
236 /* Set a callback for the instruction cycle of the CPU.
237 * You must enable M68K_INSTRUCTION_HOOK in m68kconf.h.
238 * The CPU calls this callback just before fetching the opcode in the
240 * Default behavior: do nothing.
242 void m68k_set_instr_hook_callback(void (*callback)(void));
246 /* ======================================================================== */
247 /* ====================== FUNCTIONS TO ACCESS THE CPU ===================== */
248 /* ======================================================================== */
250 /* Use this function to set the CPU type you want to emulate.
251 * Currently supported types are: M68K_CPU_TYPE_68000, M68K_CPU_TYPE_68010,
252 * M68K_CPU_TYPE_EC020, and M68K_CPU_TYPE_68020.
254 void m68k_set_cpu_type(unsigned int cpu_type);
256 /* Pulse the RESET pin on the CPU.
257 * You *MUST* reset the CPU at least once to initialize the emulation
258 * Note: If you didn't call m68k_set_cpu_type() before resetting
259 * the CPU for the first time, the CPU will be set to
260 * M68K_CPU_TYPE_68000.
262 void m68k_pulse_reset(void);
264 /* execute num_cycles worth of instructions. returns number of cycles used */
265 int m68k_execute(int num_cycles);
267 /* These functions let you read/write/modify the number of cycles left to run
268 * while m68k_execute() is running.
269 * These are useful if the 68k accesses a memory-mapped port on another device
270 * that requires immediate processing by another CPU.
272 int m68k_cycles_run(void); /* Number of cycles run so far */
273 int m68k_cycles_remaining(void); /* Number of cycles left */
274 void m68k_modify_timeslice(int cycles); /* Modify cycles left */
275 void m68k_end_timeslice(void); /* End timeslice now */
277 /* Set the IPL0-IPL2 pins on the CPU (IRQ).
278 * A transition from < 7 to 7 will cause a non-maskable interrupt (NMI).
279 * Setting IRQ to 0 will clear an interrupt request.
281 void m68k_set_irq(unsigned int int_level);
284 /* Halt the CPU as if you pulsed the HALT pin. */
285 void m68k_pulse_halt(void);
288 /* Context switching to allow multiple CPUs */
290 /* Get the size of the cpu context in bytes */
291 unsigned int m68k_context_size(void);
293 /* Get a cpu context */
294 unsigned int m68k_get_context(void* dst);
296 /* set the current cpu context */
297 void m68k_set_context(void* dst);
299 /* Save the current cpu context to disk.
300 * You must provide a function pointer of the form:
301 * void save_value(char* identifier, unsigned int value)
303 void m68k_save_context( void (*save_value)(char* identifier, unsigned int value));
305 /* Load a cpu context from disk.
306 * You must provide a function pointer of the form:
307 * unsigned int load_value(char* identifier)
309 void m68k_load_context(unsigned int (*load_value)(char* identifier));
313 /* Peek at the internals of a CPU context. This can either be a context
314 * retrieved using m68k_get_context() or the currently running context.
315 * If context is NULL, the currently running CPU context will be used.
317 unsigned int m68k_get_reg(void* context, m68k_register_t reg);
319 /* Poke values into the internals of the currently running CPU context */
320 void m68k_set_reg(m68k_register_t reg, unsigned int value);
322 /* Check if an instruction is valid for the specified CPU type */
323 unsigned int m68k_is_valid_instruction(unsigned int instruction, unsigned int cpu_type);
325 /* Disassemble 1 instruction using the epecified CPU type at pc. Stores
326 * disassembly in str_buff and returns the size of the instruction in bytes.
328 unsigned int m68k_disassemble(char* str_buff, unsigned int pc, unsigned int cpu_type);
331 /* ======================================================================== */
332 /* ============================= CONFIGURATION ============================ */
333 /* ======================================================================== */
335 /* Import the configuration for this build */
336 #include "m68kconf.h"
340 /* ======================================================================== */
341 /* ============================== END OF FILE ============================= */
342 /* ======================================================================== */
348 #endif /* M68K__HEADER */