add.c File Reference

Helper functions for addition operations. More...

#include "../config.h"
#include "add.h"
#include "memory.h"
#include "utils.h"

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Functions
static void	carry_handler (struct z80 *cpu)
static void	___add8_set_carry_flag (uint8_t a, uint8_t b, struct z80 *cpu)
	sets the carry flag based on the provided 8-bit operands More...
static void	___add8_set_zero_flag (uint8_t a, uint8_t b, struct z80 *cpu)
	sets the zero flag based on the provided 8-bit operands More...
static void	___add8_set_overflow_flag (uint8_t a, uint8_t b, struct z80 *cpu)
	sets the overflow flag based on the provided 8-bit operands More...
static void	___add8_set_sign_flag (uint8_t a, uint8_t b, struct z80 *cpu)
	sets the sign flag based on the provided 8-bit operands More...
static void	___add8_set_half_carry_flag (uint8_t a, uint8_t b, struct z80 *cpu)
	sets the half carry flag based on the provided 8-bit operands More...
static void	__add8_set_flags (uint8_t a, uint8_t b, struct z80 *cpu)
	wrapper to set all flags based on the provided addition operands More...
void	_add_a_reg8 (struct z80 *cpu, uint8_t *reg)
	adds the contents of a user supplied register to A More...
void	_adc_a_reg8 (struct z80 *cpu, uint8_t *reg)
	adds the contents of a user supplied register and the carry flag to A More...
void	_add_a_mem (struct z80 *cpu, uint8_t *memory)
	adds the contents of a user supplied register to A More...
void	_adc_a_mem (struct z80 *cpu, uint8_t *memory)
	adds contents of A to the contents of a memory address with carry More...
void	_add_reg16_reg16 (word *reg1, word *reg2, struct z80 *cpu)
	adds two 16-bit registers together, storing the values in reg1 More...
void	_inc8 (uint8_t *n, struct z80 *cpu)
	increments an 8 bit register More...

Detailed Description

Helper functions for addition operations.

Author

Peter H. Ezetta

Date

2018-2019

Function Documentation

___add8_set_carry_flag()

static void ___add8_set_carry_flag ( uint8_t  a, uint8_t  b, struct z80 *  cpu  )

static

sets the carry flag based on the provided 8-bit operands

Parameters

a	first operand
b	second operand
cpu	z80 cpu object

___add8_set_half_carry_flag()

static void ___add8_set_half_carry_flag ( uint8_t  a, uint8_t  b, struct z80 *  cpu  )

static

sets the half carry flag based on the provided 8-bit operands

Parameters

a	first operand
b	second operand
cpu	z80 cpu object

The H flag is set when there is a carry from bit 3 to bit 4.

___add8_set_overflow_flag()

static void ___add8_set_overflow_flag ( uint8_t  a, uint8_t  b, struct z80 *  cpu  )

static

sets the overflow flag based on the provided 8-bit operands

Parameters

a	first operand
b	second operand
cpu	z80 cpu object

For addition operations, the P/V flag is used for overflow. It is set when the 2's Complement result of the operation will not fit in the register.

___add8_set_sign_flag()

static void ___add8_set_sign_flag ( uint8_t  a, uint8_t  b, struct z80 *  cpu  )

static

sets the sign flag based on the provided 8-bit operands

Parameters

a	first operand
b	second operand
cpu	z80 cpu object

The S flag is a copy of bit 7 of the result of the operation.

___add8_set_zero_flag()

static void ___add8_set_zero_flag ( uint8_t  a, uint8_t  b, struct z80 *  cpu  )

static

sets the zero flag based on the provided 8-bit operands

Parameters

a	first operand
b	second operand
cpu	z80 cpu object

__add8_set_flags()

static void __add8_set_flags ( uint8_t  a, uint8_t  b, struct z80 *  cpu  )

static

wrapper to set all flags based on the provided addition operands

Parameters

a	first operand
b	second operand
cpu	z80 cpu object

Note

INC doesn't effect C. Do not use this with _inc8() et al.

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_adc_a_mem()

void _adc_a_mem	(	struct z80 *	cpu,
		uint8_t *	memory
	)

adds contents of A to the contents of a memory address with carry

Parameters

cpu	z80 cpu object
memory	memory location to add to A

_adc_a_reg8()

void _adc_a_reg8	(	struct z80 *	cpu,
		uint8_t *	reg
	)

adds the contents of a user supplied register and the carry flag to A

Parameters

cpu	z80 cpu object
reg	register to add to A

_add_a_mem()

void _add_a_mem	(	struct z80 *	cpu,
		uint8_t *	memory
	)

adds the contents of a user supplied register to A

Parameters

cpu	z80 cpu object
memory	pointer to system memory

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_add_a_reg8()

void _add_a_reg8	(	struct z80 *	cpu,
		uint8_t *	reg
	)

adds the contents of a user supplied register to A

Parameters

cpu	z80 cpu object
reg	register to add to A

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_add_reg16_reg16()

void _add_reg16_reg16	(	word *	reg1,
		word *	reg2,
		struct z80 *	cpu
	)

adds two 16-bit registers together, storing the values in reg1

Parameters

reg1	the first register for the add operation
reg2	the second register for the add operation
cpu	z80 cpu object

_inc8()

void _inc8	(	uint8_t *	n,
		struct z80 *	cpu
	)

increments an 8 bit register

Parameters

n	pointer to register to increment
cpu	z80 cpu object

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