6502.c File Reference

#include <emulation/CPU/6502.h>

Include dependency graph for 6502.c:

Macros
#define	CPU_6502_API   Z_API_EXPORT
#define	READ_8(address)    object->read (object->context, (zuint16)(address))
#define	WRITE_8(address, value)    object->write(object->context, (zuint16)(address), (zuint8)(value))
#define	READ_16(address)   read_16bit (object, (zuint16)(address))
#define	READ_POINTER(pointer_name)   READ_16(Z_6502_ADDRESS_##pointer_name##_POINTER)
#define	PC   object->state.Z_6502_STATE_MEMBER_PC
#define	S   object->state.Z_6502_STATE_MEMBER_S
#define	P   object->state.Z_6502_STATE_MEMBER_P
#define	A   object->state.Z_6502_STATE_MEMBER_A
#define	X   object->state.Z_6502_STATE_MEMBER_X
#define	Y   object->state.Z_6502_STATE_MEMBER_Y
#define	NMI   object->state.Z_6502_STATE_MEMBER_NMI
#define	IRQ   object->state.Z_6502_STATE_MEMBER_IRQ
#define	CYCLES   object->cycles
#define	OPCODE   object->opcode
#define	EA   object->ea
#define	EA_CYCLES   object->ea_cycles
#define	NP   128
#define	VP   64
#define	BP   16
#define	DP   8
#define	IP   4
#define	ZP   2
#define	CP   1
#define	NZP   (NP | ZP)
#define	NZCP   (NP | ZP | CP)
#define	ZP_ZERO(value)   (!(value) << 1)
#define	SET_P_NZ(value)   P = (P & ~NZP) | ((value) ? ((value) & NP) : ZP)
#define	PUSH_8(value)   WRITE_8(Z_6502_ADDRESS_STACK + S--, value);
#define	POP_8   READ_8 (Z_6502_ADDRESS_STACK + ++S)
#define	PUSH_16(value)   push_16bit(object, value)
#define	POP_16   pop_16bit(object)
#define	READ_BYTE_OPERAND   READ_8 ((PC += 2) - 1)
#define	READ_WORD_OPERAND   READ_16((PC += 3) - 2)
#define	ZERO_PAGE_ADDRESS   READ_BYTE_OPERAND
#define	ZERO_PAGE_X_ADDRESS   (zuint8)(READ_BYTE_OPERAND + X)
#define	ZERO_PAGE_Y_ADDRESS   (zuint8)(READ_BYTE_OPERAND + Y)
#define	ABSOLUTE_ADDRESS   READ_WORD_OPERAND
#define	ABSOLUTE_X_ADDRESS   READ_WORD_OPERAND + X
#define	ABSOLUTE_Y_ADDRESS   READ_WORD_OPERAND + Y
#define	INDIRECT_X_ADDRESS   READ_16((zuint8)(READ_BYTE_OPERAND + X))
#define	INDIRECT_Y_ADDRESS   READ_16(READ_BYTE_OPERAND) + Y
#define	EA_READER(name)   static zuint8 read_##name (M6502 *object)
#define	EA_WRITER(name)   static void write_##name(M6502 *object, zuint8 value)
#define	EA_INDEX   (OPCODE & 28) >> 2
#define	READ_J   read_j_table [EA_INDEX](object)
#define	READ_G   read_g_table [EA_INDEX](object)
#define	READ_H   read_h_table [EA_INDEX](object)
#define	READ_Q   read_q_table [EA_INDEX](object)
#define	WRITE_K(value)   write_k_table[EA_INDEX](object, value)
#define	WRITE_H(value)   write_h_table[EA_INDEX](object, value)
#define	WRITE_Q(value)   write_q_table[EA_INDEX](object, value)
#define	WRITE_G(value)   if (EA_CYCLES == 2) A = value; else WRITE_8(EA, value);
#define	INSTRUCTION(name)   static zuint8 name(M6502 *object)
#define	COMPARE(register, ea_table)
#define	BRANCH(flag_mask, condition_logic)
#define	BRANCH_IF_CLEAR(flag_mask)   BRANCH(flag_mask, !)
#define	BRANCH_IF_SET( flag_mask)   BRANCH(flag_mask, Z_EMPTY)
#define	INC_DEC(operation)

Typedefs
typedef zuint8(*	Instruction) (M6502 *object)
typedef zuint8(*	ReadEA) (M6502 *object)
typedef void(*	WriteEA) (M6502 *object, zuint8 value)

Functions
static Z_INLINE zuint16	read_16bit (M6502 *object, zuint16 address)
static Z_INLINE void	push_16bit (M6502 *object, zuint16 value)
static Z_INLINE zuint16	pop_16bit (M6502 *object)
	EA_READER (accumulator)
	EA_READER (immediate)
	EA_READER (zero_page)
	EA_READER (zero_page_x)
	EA_READER (zero_page_y)
	EA_READER (absolute)
	EA_READER (indirect_x)
	EA_READER (g_zero_page)
	EA_READER (g_zero_page_x)
	EA_READER (g_absolute)
	EA_READER (g_absolute_x)
	EA_READER (penalized_absolute_x)
	EA_READER (penalized_absolute_y)
	EA_READER (penalized_indirect_y)
	EA_WRITER (zero_page)
	EA_WRITER (zero_page_x)
	EA_WRITER (zero_page_y)
	EA_WRITER (absolute)
	EA_WRITER (absolute_x)
	EA_WRITER (absolute_y)
	EA_WRITER (indirect_x)
	EA_WRITER (indirect_y)
	INSTRUCTION (lda_J)
	INSTRUCTION (ldx_H)
	INSTRUCTION (ldy_Q)
	INSTRUCTION (sta_K)
	INSTRUCTION (stx_H)
	INSTRUCTION (sty_Q)
	INSTRUCTION (tax)
	INSTRUCTION (tay)
	INSTRUCTION (txa)
	INSTRUCTION (tya)
	INSTRUCTION (tsx)
	INSTRUCTION (txs)
	INSTRUCTION (pha)
	INSTRUCTION (php)
	INSTRUCTION (pla)
	INSTRUCTION (plp)
	INSTRUCTION (and_J)
	INSTRUCTION (eor_J)
	INSTRUCTION (ora_J)
	INSTRUCTION (bit_Q)
	INSTRUCTION (cmp_J)
	INSTRUCTION (cpx_Q)
	INSTRUCTION (cpy_Q)
	INSTRUCTION (adc_J)
	INSTRUCTION (sbc_J)
	INSTRUCTION (inc_G)
	INSTRUCTION (inx)
	INSTRUCTION (iny)
	INSTRUCTION (dec_G)
	INSTRUCTION (dex)
	INSTRUCTION (dey)
	INSTRUCTION (asl_G)
	INSTRUCTION (lsr_G)
	INSTRUCTION (rol_G)
	INSTRUCTION (ror_G)
	INSTRUCTION (jmp_WORD)
	INSTRUCTION (jmp_vWORD)
	INSTRUCTION (jsr_WORD)
	INSTRUCTION (rts)
	INSTRUCTION (bcc_OFFSET)
	INSTRUCTION (bcs_OFFSET)
	INSTRUCTION (beq_OFFSET)
	INSTRUCTION (bmi_OFFSET)
	INSTRUCTION (bne_OFFSET)
	INSTRUCTION (bpl_OFFSET)
	INSTRUCTION (bvc_OFFSET)
	INSTRUCTION (bvs_OFFSET)
	INSTRUCTION (clc)
	INSTRUCTION (cld)
	INSTRUCTION (cli)
	INSTRUCTION (clv)
	INSTRUCTION (sec)
	INSTRUCTION (sed)
	INSTRUCTION (sei)
	INSTRUCTION (nop)
	INSTRUCTION (rti)
	INSTRUCTION (brk)
	INSTRUCTION (illegal)
CPU_6502_API void	m6502_power (M6502 *object, zboolean state)
	Changes the CPU power status. More...
CPU_6502_API void	m6502_reset (M6502 *object)
	Resets the CPU. More...
CPU_6502_API zusize	m6502_run (M6502 *object, zusize cycles)
	Runs the CPU for a given number of cycles. More...
CPU_6502_API void	m6502_nmi (M6502 *object)
	Performs a non-maskable interrupt (NMI). More...
CPU_6502_API void	m6502_irq (M6502 *object, zboolean state)
	Changes the state of the maskable interrupt (IRQ). More...

Variables
static ReadEA const	read_j_table [8]
static WriteEA const	write_k_table [8]
static ReadEA const	read_g_table [8]
static ReadEA const	read_h_table [8]
static WriteEA const	write_h_table [8]
static ReadEA const	read_q_table [8]
static WriteEA const	write_q_table [6]
static Instruction const	instruction_table [256]

Macro Definition Documentation

CPU_6502_API

#define CPU_6502_API   Z_API_EXPORT

READ_8

#define READ_8

(

address

)

object->read (object->context, (zuint16)(address))

WRITE_8

#define WRITE_8	(		address,
			value
	)		object->write(object->context, (zuint16)(address), (zuint8)(value))

READ_16

#define READ_16

(

address

)

read_16bit (object, (zuint16)(address))

READ_POINTER

#define READ_POINTER

(

pointer_name

)

READ_16(Z_6502_ADDRESS_##pointer_name##_POINTER)

PC

#define PC   object->state.Z_6502_STATE_MEMBER_PC

S

#define S   object->state.Z_6502_STATE_MEMBER_S

P

#define P   object->state.Z_6502_STATE_MEMBER_P

A

#define A   object->state.Z_6502_STATE_MEMBER_A

X

#define X   object->state.Z_6502_STATE_MEMBER_X

Y

#define Y   object->state.Z_6502_STATE_MEMBER_Y

NMI

#define NMI   object->state.Z_6502_STATE_MEMBER_NMI

IRQ

#define IRQ   object->state.Z_6502_STATE_MEMBER_IRQ

CYCLES

#define CYCLES   object->cycles

OPCODE

#define OPCODE   object->opcode

EA

#define EA   object->ea

EA_CYCLES

#define EA_CYCLES   object->ea_cycles

NP

#define NP   128

VP

#define VP   64

BP

#define BP   16

DP

#define DP   8

IP

#define IP   4

ZP

#define ZP   2

CP

#define CP   1

NZP

#define NZP   (NP | ZP)

NZCP

#define NZCP   (NP | ZP | CP)

ZP_ZERO

#define ZP_ZERO

(

value

)

(!(value) << 1)

SET_P_NZ

#define SET_P_NZ

(

value

)

P = (P & ~NZP) | ((value) ? ((value) & NP) : ZP)

PUSH_8

#define PUSH_8

(

value

)

WRITE_8(Z_6502_ADDRESS_STACK + S--, value);

POP_8

#define POP_8   READ_8 (Z_6502_ADDRESS_STACK + ++S)

PUSH_16

#define PUSH_16

(

value

)

push_16bit(object, value)

POP_16

#define POP_16   pop_16bit(object)

READ_BYTE_OPERAND

#define READ_BYTE_OPERAND   READ_8 ((PC += 2) - 1)

READ_WORD_OPERAND

#define READ_WORD_OPERAND   READ_16((PC += 3) - 2)

ZERO_PAGE_ADDRESS

#define ZERO_PAGE_ADDRESS   READ_BYTE_OPERAND

ZERO_PAGE_X_ADDRESS

#define ZERO_PAGE_X_ADDRESS   (zuint8)(READ_BYTE_OPERAND + X)

ZERO_PAGE_Y_ADDRESS

#define ZERO_PAGE_Y_ADDRESS   (zuint8)(READ_BYTE_OPERAND + Y)

ABSOLUTE_ADDRESS

#define ABSOLUTE_ADDRESS   READ_WORD_OPERAND

ABSOLUTE_X_ADDRESS

#define ABSOLUTE_X_ADDRESS   READ_WORD_OPERAND + X

ABSOLUTE_Y_ADDRESS

#define ABSOLUTE_Y_ADDRESS   READ_WORD_OPERAND + Y

INDIRECT_X_ADDRESS

#define INDIRECT_X_ADDRESS   READ_16((zuint8)(READ_BYTE_OPERAND + X))

INDIRECT_Y_ADDRESS

#define INDIRECT_Y_ADDRESS   READ_16(READ_BYTE_OPERAND) + Y

EA_READER

#define EA_READER

(

name

)

static zuint8 read_##name (M6502 *object)

EA_WRITER

#define EA_WRITER

(

name

)

static void write_##name(M6502 *object, zuint8 value)

EA_INDEX

#define EA_INDEX   (OPCODE & 28) >> 2

READ_J

#define READ_J   read_j_table [EA_INDEX](object)

READ_G

#define READ_G   read_g_table [EA_INDEX](object)

READ_H

#define READ_H   read_h_table [EA_INDEX](object)

READ_Q

#define READ_Q   read_q_table [EA_INDEX](object)

WRITE_K

#define WRITE_K

(

value

)

write_k_table[EA_INDEX](object, value)

WRITE_H

#define WRITE_H

(

value

)

write_h_table[EA_INDEX](object, value)

WRITE_Q

#define WRITE_Q

(

value

)

write_q_table[EA_INDEX](object, value)

WRITE_G

#define WRITE_G

(

value

)

if (EA_CYCLES == 2) A = value; else WRITE_8(EA, value);

INSTRUCTION

#define INSTRUCTION

(

name

)

static zuint8 name(M6502 *object)

COMPARE

#define COMPARE	(		register,
			ea_table
	)

Value:

        zuint8 v = READ_##ea_table;                                               \
        zuint8 result = register - v;                                             \
                                                                                  \
        P = (zuint8)                                                              \
                ((P & ~NZCP)           /* VP, XP, BP, DP, IP unchanged         */ \
                 | (result & NP)       /* NP = result.7                        */ \
                 | ZP_ZERO(result)     /* ZP = 1 if result = 0, else ZP = 0    */ \
                 | !!(register >= v)); /* CP = 1 if register >= v, else CP = 0 */ \
                                                                                  \
        return EA_CYCLES;

BRANCH

#define BRANCH	(		flag_mask,
			condition_logic
	)

Value:

        zuint8 cycles = 2;                              \
                                                        \
        if (condition_logic(P & flag_mask))             \
                {                                       \
                zuint16 pc = PC + 2;                    \
                zsint8 offset = (zsint8)READ_8(PC + 1); \
                zuint16 t = (zuint16)(pc + offset);     \
                                                        \
                if (t >> 8 == pc >> 8) cycles++;        \
                else cycles += 2;                       \
                PC = t;                                 \
                }                                       \
                                                        \
        else PC += 2;                                   \
                                                        \
        return cycles;

BRANCH_IF_CLEAR

#define BRANCH_IF_CLEAR

(

flag_mask

)

BRANCH(flag_mask, !)

BRANCH_IF_SET

#define BRANCH_IF_SET

(

flag_mask

)

BRANCH(flag_mask, Z_EMPTY)

INC_DEC

#define INC_DEC

(

operation

)

Value:

        zuint8 t = READ_G operation 1;  \
					\
	WRITE_G(t);                    \
        SET_P_NZ(t);                    \
        return EA_CYCLES;

Typedef Documentation

Instruction

typedef zuint8(* Instruction) (M6502 *object)

ReadEA

typedef zuint8(* ReadEA) (M6502 *object)

WriteEA

typedef void(* WriteEA) (M6502 *object, zuint8 value)

Function Documentation

read_16bit()

static Z_INLINE zuint16 read_16bit ( M6502 *  object, zuint16  address  )

static

References READ_8.

push_16bit()

static Z_INLINE void push_16bit ( M6502 *  object, zuint16  value  )

static

References S, WRITE_8, and Z_6502_ADDRESS_STACK.

pop_16bit()

static Z_INLINE zuint16 pop_16bit ( M6502 *  object )

static

References READ_8, S, and Z_6502_ADDRESS_STACK.

EA_READER() [1/14]

EA_READER

(

accumulator

)

References A, EA_CYCLES, and PC.

EA_READER() [2/14]

EA_READER

(

immediate

)

References EA_CYCLES, and READ_BYTE_OPERAND.

EA_READER() [3/14]

EA_READER

(

zero_page

)

References EA_CYCLES, READ_8, and ZERO_PAGE_ADDRESS.

EA_READER() [4/14]

EA_READER

(

zero_page_x

)

References EA_CYCLES, READ_8, and ZERO_PAGE_X_ADDRESS.

EA_READER() [5/14]

EA_READER

(

zero_page_y

)

References EA_CYCLES, READ_8, and ZERO_PAGE_Y_ADDRESS.

EA_READER() [6/14]

EA_READER

(

absolute

)

References ABSOLUTE_ADDRESS, EA_CYCLES, and READ_8.

EA_READER() [7/14]

EA_READER

(

indirect_x

)

References EA_CYCLES, INDIRECT_X_ADDRESS, and READ_8.

EA_READER() [8/14]

EA_READER

(

g_zero_page

)

References EA, EA_CYCLES, READ_8, and ZERO_PAGE_ADDRESS.

EA_READER() [9/14]

EA_READER

(

g_zero_page_x

)

References EA, EA_CYCLES, READ_8, and ZERO_PAGE_X_ADDRESS.

EA_READER() [10/14]

EA_READER

(

g_absolute

)

References ABSOLUTE_ADDRESS, EA, EA_CYCLES, and READ_8.

EA_READER() [11/14]

EA_READER

(

g_absolute_x

)

References ABSOLUTE_X_ADDRESS, EA, EA_CYCLES, and READ_8.

EA_READER() [12/14]

EA_READER

(

penalized_absolute_x

)

References EA_CYCLES, READ_8, READ_WORD_OPERAND, and X.

EA_READER() [13/14]

EA_READER

(

penalized_absolute_y

)

References EA_CYCLES, READ_8, READ_WORD_OPERAND, and Y.

EA_READER() [14/14]

EA_READER

(

penalized_indirect_y

)

References EA_CYCLES, READ_16, READ_8, READ_BYTE_OPERAND, and Y.

EA_WRITER() [1/8]

EA_WRITER

(

zero_page

)

References EA_CYCLES, WRITE_8, and ZERO_PAGE_ADDRESS.

EA_WRITER() [2/8]

EA_WRITER

(

zero_page_x

)

References EA_CYCLES, WRITE_8, and ZERO_PAGE_X_ADDRESS.

EA_WRITER() [3/8]

EA_WRITER

(

zero_page_y

)

References EA_CYCLES, WRITE_8, and ZERO_PAGE_Y_ADDRESS.

EA_WRITER() [4/8]

EA_WRITER

(

absolute

)

References ABSOLUTE_ADDRESS, EA_CYCLES, and WRITE_8.

EA_WRITER() [5/8]

EA_WRITER

(

absolute_x

)

References ABSOLUTE_X_ADDRESS, EA_CYCLES, and WRITE_8.

EA_WRITER() [6/8]

EA_WRITER

(

absolute_y

)

References ABSOLUTE_Y_ADDRESS, EA_CYCLES, and WRITE_8.

EA_WRITER() [7/8]

EA_WRITER

(

indirect_x

)

References EA_CYCLES, INDIRECT_X_ADDRESS, and WRITE_8.

EA_WRITER() [8/8]

EA_WRITER

(

indirect_y

)

References EA_CYCLES, INDIRECT_Y_ADDRESS, and WRITE_8.

INSTRUCTION() [1/58]

INSTRUCTION

(

lda_J

)

References A, EA_CYCLES, READ_J, and SET_P_NZ.

INSTRUCTION() [2/58]

INSTRUCTION

(

ldx_H

)

References EA_CYCLES, READ_H, SET_P_NZ, and X.

INSTRUCTION() [3/58]

INSTRUCTION

(

ldy_Q

)

References EA_CYCLES, READ_Q, SET_P_NZ, and Y.

INSTRUCTION() [4/58]

INSTRUCTION

(

sta_K

)

References A, EA_CYCLES, and WRITE_K.

INSTRUCTION() [5/58]

INSTRUCTION

(

stx_H

)

References EA_CYCLES, WRITE_H, and X.

INSTRUCTION() [6/58]

INSTRUCTION

(

sty_Q

)

References EA_CYCLES, WRITE_Q, and Y.

INSTRUCTION() [7/58]

INSTRUCTION

(

tax

)

References A, PC, SET_P_NZ, and X.

INSTRUCTION() [8/58]

INSTRUCTION

(

tay

)

References A, PC, SET_P_NZ, and Y.

INSTRUCTION() [9/58]

INSTRUCTION

(

txa

)

References A, PC, SET_P_NZ, and X.

INSTRUCTION() [10/58]

INSTRUCTION

(

tya

)

References A, PC, SET_P_NZ, and Y.

INSTRUCTION() [11/58]

INSTRUCTION

(

tsx

)

References PC, S, SET_P_NZ, and X.

INSTRUCTION() [12/58]

INSTRUCTION

(

txs

)

References PC, S, and X.

INSTRUCTION() [13/58]

INSTRUCTION

(

pha

)

References A, PC, and PUSH_8.

INSTRUCTION() [14/58]

INSTRUCTION

(

php

)

References P, PC, and PUSH_8.

INSTRUCTION() [15/58]

INSTRUCTION

(

pla

)

References A, PC, POP_8, and SET_P_NZ.

INSTRUCTION() [16/58]

INSTRUCTION

(

plp

)

References P, PC, and POP_8.

INSTRUCTION() [17/58]

INSTRUCTION

(

and_J

)

References A, EA_CYCLES, READ_J, and SET_P_NZ.

INSTRUCTION() [18/58]

INSTRUCTION

(

eor_J

)

References A, EA_CYCLES, READ_J, and SET_P_NZ.

INSTRUCTION() [19/58]

INSTRUCTION

(

ora_J

)

References A, EA_CYCLES, READ_J, and SET_P_NZ.

INSTRUCTION() [20/58]

INSTRUCTION

(

bit_Q

)

References A, EA_CYCLES, NP, P, READ_Q, VP, and ZP.

INSTRUCTION() [21/58]

INSTRUCTION

(

cmp_J

)

References A, and COMPARE.

INSTRUCTION() [22/58]

INSTRUCTION

(

cpx_Q

)

References COMPARE, and X.

INSTRUCTION() [23/58]

INSTRUCTION

(

cpy_Q

)

References COMPARE, and Y.

INSTRUCTION() [24/58]

INSTRUCTION

(

adc_J

)

References A, CP, DP, EA_CYCLES, NP, P, READ_J, SET_P_NZ, VP, and ZP.

INSTRUCTION() [25/58]

INSTRUCTION

(

sbc_J

)

References A, CP, DP, EA_CYCLES, NP, P, READ_J, SET_P_NZ, VP, and ZP.

INSTRUCTION() [26/58]

INSTRUCTION

(

inc_G

)

References INC_DEC.

INSTRUCTION() [27/58]

INSTRUCTION

(

inx

)

References PC, SET_P_NZ, and X.

INSTRUCTION() [28/58]

INSTRUCTION

(

iny

)

References PC, SET_P_NZ, and Y.

INSTRUCTION() [29/58]

INSTRUCTION

(

dec_G

)

References INC_DEC.

INSTRUCTION() [30/58]

INSTRUCTION

(

dex

)

References PC, SET_P_NZ, and X.

INSTRUCTION() [31/58]

INSTRUCTION

(

dey

)

References PC, SET_P_NZ, and Y.

INSTRUCTION() [32/58]

INSTRUCTION

(

asl_G

)

References EA_CYCLES, NP, NZCP, P, READ_G, WRITE_G, and ZP_ZERO.

INSTRUCTION() [33/58]

INSTRUCTION

(

lsr_G

)

References CP, EA_CYCLES, NZCP, P, READ_G, WRITE_G, and ZP_ZERO.

INSTRUCTION() [34/58]

INSTRUCTION

(

rol_G

)

References CP, EA_CYCLES, NP, NZCP, P, READ_G, WRITE_G, and ZP_ZERO.

INSTRUCTION() [35/58]

INSTRUCTION

(

ror_G

)

References CP, EA_CYCLES, NP, NZCP, P, READ_G, WRITE_G, and ZP_ZERO.

INSTRUCTION() [36/58]

INSTRUCTION

(

jmp_WORD

)

References PC, and READ_16.

INSTRUCTION() [37/58]

INSTRUCTION

(

jmp_vWORD

)

References PC, and READ_16.

INSTRUCTION() [38/58]

INSTRUCTION

(

jsr_WORD

)

References PC, PUSH_16, and READ_16.

INSTRUCTION() [39/58]

INSTRUCTION

(

rts

)

References PC, and POP_16.

INSTRUCTION() [40/58]

INSTRUCTION

(

bcc_OFFSET

)

References BRANCH_IF_CLEAR, and CP.

INSTRUCTION() [41/58]

INSTRUCTION

(

bcs_OFFSET

)

References BRANCH_IF_SET, and CP.

INSTRUCTION() [42/58]

INSTRUCTION

(

beq_OFFSET

)

References BRANCH_IF_SET, and ZP.

INSTRUCTION() [43/58]

INSTRUCTION

(

bmi_OFFSET

)

References BRANCH_IF_SET, and NP.

INSTRUCTION() [44/58]

INSTRUCTION

(

bne_OFFSET

)

References BRANCH_IF_CLEAR, and ZP.

INSTRUCTION() [45/58]

INSTRUCTION

(

bpl_OFFSET

)

References BRANCH_IF_CLEAR, and NP.

INSTRUCTION() [46/58]

INSTRUCTION

(

bvc_OFFSET

)

References BRANCH_IF_CLEAR, and VP.

INSTRUCTION() [47/58]

INSTRUCTION

(

bvs_OFFSET

)

References BRANCH_IF_SET, and VP.

INSTRUCTION() [48/58]

INSTRUCTION

(

clc

)

References P, and PC.

INSTRUCTION() [49/58]

INSTRUCTION

(

cld

)

References P, and PC.

INSTRUCTION() [50/58]

INSTRUCTION

(

cli

)

References P, and PC.

INSTRUCTION() [51/58]

INSTRUCTION

(

clv

)

References P, and PC.

INSTRUCTION() [52/58]

INSTRUCTION

(

sec

)

References CP, P, and PC.

INSTRUCTION() [53/58]

INSTRUCTION

(

sed

)

References DP, P, and PC.

INSTRUCTION() [54/58]

INSTRUCTION

(

sei

)

References IP, P, and PC.

INSTRUCTION() [55/58]

INSTRUCTION

(

nop

)

References PC.

INSTRUCTION() [56/58]

INSTRUCTION

(

rti

)

References P, PC, POP_16, and POP_8.

INSTRUCTION() [57/58]

INSTRUCTION

(

brk

)

References BP, IP, P, PC, PUSH_16, PUSH_8, READ_8, and READ_POINTER.

INSTRUCTION() [58/58]

INSTRUCTION

(

illegal

)

m6502_power()

CPU_6502_API void m6502_power	(	M6502 *	object,
		zboolean	state
	)

Changes the CPU power status.

Parameters

object	A pointer to a 6502 emulator instance.
state	TRUE = power ON; FALSE = power OFF.

References A, FALSE, IRQ, NMI, P, PC, S, X, Y, Z_6502_VALUE_AFTER_POWER_ON_A, Z_6502_VALUE_AFTER_POWER_ON_P, Z_6502_VALUE_AFTER_POWER_ON_PC, Z_6502_VALUE_AFTER_POWER_ON_S, Z_6502_VALUE_AFTER_POWER_ON_X, and Z_6502_VALUE_AFTER_POWER_ON_Y.

Referenced by C64_LoadPrg().

m6502_reset()

CPU_6502_API void m6502_reset

(

M6502 *

object

)

Resets the CPU.

This is equivalent to a pulse on the RESET line of a real 6502.

Parameters

object

A pointer to a 6502 emulator instance.

References FALSE, IRQ, NMI, P, PC, READ_POINTER, S, Z_6502_VALUE_AFTER_POWER_ON_P, and Z_6502_VALUE_AFTER_POWER_ON_S.

m6502_run()

CPU_6502_API zusize m6502_run	(	M6502 *	object,
		zusize	cycles
	)

Runs the CPU for a given number of cycles.

Parameters

object	A pointer to a 6502 emulator instance.
cycles	The number of cycles to be executed.

Returns

The number of cycles executed.

Note

Given the fact that one 6502 instruction needs between 2 and 7 cycles to be executed, it's not always possible to run the CPU the exact number of cycles specfified.

References CYCLES, FALSE, instruction_table, IP, IRQ, NMI, OPCODE, P, PC, PUSH_16, PUSH_8, READ_8, and READ_POINTER.

Referenced by C64_LoadPrg().

m6502_nmi()

CPU_6502_API void m6502_nmi

(

M6502 *

object

)

Performs a non-maskable interrupt (NMI).

This is equivalent to a pulse on the NMI line of a real 6502.

Parameters

object

A pointer to a 6502 emulator instance.

References NMI, and TRUE.

m6502_irq()

CPU_6502_API void m6502_irq	(	M6502 *	object,
		zboolean	state
	)

Changes the state of the maskable interrupt (IRQ).

This is equivalent to a change on the IRQ line of a real 6502.

Parameters

object	A pointer to a 6502 emulator instance.
state	TRUE = line high; FALSE = line low.

References IRQ.

Referenced by C64_LoadPrg(), and C64_mem_write().

Variable Documentation

read_j_table

ReadEA const read_j_table[8]

static

Initial value:

= {
         read_indirect_x,
         read_zero_page,
         read_immediate,
         read_absolute,
         read_penalized_indirect_y,
         read_zero_page_x,
         read_penalized_absolute_y,
         read_penalized_absolute_x
}

write_k_table

WriteEA const write_k_table[8]

static

Initial value:

= {
         write_indirect_x,
         write_zero_page,
         NULL,
         write_absolute,
         write_indirect_y,
         write_zero_page_x,
         write_absolute_y,
         write_absolute_x
}

read_g_table

ReadEA const read_g_table[8]

static

Initial value:

= {
         NULL,
         read_g_zero_page,
         read_accumulator,
         read_g_absolute,
         NULL,
         read_g_zero_page_x,
         NULL,
         read_g_absolute_x
}

read_h_table

ReadEA const read_h_table[8]

static

Initial value:

= {
         read_immediate,
         read_zero_page,
         NULL,
         read_absolute,
         NULL,
         read_zero_page_y,
         NULL,
         read_penalized_absolute_y
}

write_h_table

WriteEA const write_h_table[8]

static

Initial value:

= {
         NULL,
         write_zero_page,
         NULL,
         write_absolute,
         NULL,
         write_zero_page_y
}

read_q_table

ReadEA const read_q_table[8]

static

Initial value:

= {
         read_immediate,
         read_zero_page,
         NULL,
         read_absolute,
         NULL,
         read_zero_page_x,
         NULL,
         read_penalized_absolute_x
}

write_q_table

WriteEA const write_q_table[6]

static

Initial value:

= {
         NULL,
         write_zero_page,
         NULL,
         write_absolute,
         NULL,
         write_zero_page_x
}

instruction_table

Instruction const instruction_table[256]

static

Initial value:

= {
 
        brk,        ora_J, illegal, illegal, illegal, ora_J, asl_G, illegal, php, ora_J,   asl_G,   illegal, illegal,   ora_J, asl_G,   illegal,
        bpl_OFFSET, ora_J, illegal, illegal, illegal, ora_J, asl_G, illegal, clc, ora_J,   illegal, illegal, illegal,   ora_J, asl_G,   illegal,
        jsr_WORD,   and_J, illegal, illegal, bit_Q,   and_J, rol_G, illegal, plp, and_J,   rol_G,   illegal, bit_Q,     and_J, rol_G,   illegal,
        bmi_OFFSET, and_J, illegal, illegal, illegal, and_J, rol_G, illegal, sec, and_J,   illegal, illegal, illegal,   and_J, rol_G,   illegal,
        rti,        eor_J, illegal, illegal, illegal, eor_J, lsr_G, illegal, pha, eor_J,   lsr_G,   illegal, jmp_WORD,  eor_J, lsr_G,   illegal,
        bvc_OFFSET, eor_J, illegal, illegal, illegal, eor_J, lsr_G, illegal, cli, eor_J,   illegal, illegal, illegal,   eor_J, lsr_G,   illegal,
        rts,        adc_J, illegal, illegal, illegal, adc_J, ror_G, illegal, pla, adc_J,   ror_G,   illegal, jmp_vWORD, adc_J, ror_G,   illegal,
        bvs_OFFSET, adc_J, illegal, illegal, illegal, adc_J, ror_G, illegal, sei, adc_J,   illegal, illegal, illegal,   adc_J, ror_G,   illegal,
        illegal,    sta_K, illegal, illegal, sty_Q,   sta_K, stx_H, illegal, dey, illegal, txa,     illegal, sty_Q,     sta_K, stx_H,   illegal,
        bcc_OFFSET, sta_K, illegal, illegal, sty_Q,   sta_K, stx_H, illegal, tya, sta_K,   txs,     illegal, illegal,   sta_K, illegal, illegal,
        ldy_Q,      lda_J, ldx_H,   illegal, ldy_Q,   lda_J, ldx_H, illegal, tay, lda_J,   tax,     illegal, ldy_Q,     lda_J, ldx_H,   illegal,
        bcs_OFFSET, lda_J, illegal, illegal, ldy_Q,   lda_J, ldx_H, illegal, clv, lda_J,   tsx,     illegal, ldy_Q,     lda_J, ldx_H,   illegal,
        cpy_Q,      cmp_J, illegal, illegal, cpy_Q,   cmp_J, dec_G, illegal, iny, cmp_J,   dex,     illegal, cpy_Q,     cmp_J, dec_G,   illegal,
        bne_OFFSET, cmp_J, illegal, illegal, illegal, cmp_J, dec_G, illegal, cld, cmp_J,   illegal, illegal, illegal,   cmp_J, dec_G,   illegal,
        cpx_Q,      sbc_J, illegal, illegal, cpx_Q,   sbc_J, inc_G, illegal, inx, sbc_J,   nop,     illegal, cpx_Q,     sbc_J, inc_G,   illegal,
        beq_OFFSET, sbc_J, illegal, illegal, illegal, sbc_J, inc_G, illegal, sed, sbc_J,   illegal, illegal, illegal,   sbc_J, inc_G,   illegal
}

Referenced by m6502_run().