Common Macros

Utility macros. More...

Macros
#define	ARRAY_SIZE(arr)
	Get number of elements in array.
#define	BIT(n)
	Create a bit mask.
#define	CLAMP(x, lo, hi)
	Clamp value to range.
#define	HI_BYTE(x)
	Get high byte of 16-bit value.
#define	LO_BYTE(x)
	Get low byte of 16-bit value.
#define	MAKE_WORD(lo, hi)
	Combine two bytes into 16-bit value.
#define	MAX(a, b)
	Get maximum of two values.
#define	MIN(a, b)
	Get minimum of two values.
#define	NULL   ((void*)0)
	Null pointer constant.

Detailed Description

Utility macros.

Macro Definition Documentation

ARRAY_SIZE

#define ARRAY_SIZE

(

arr

)

Value:

(sizeof(arr) / sizeof((arr)[0]))

Get number of elements in array.

Parameters

arr	Array variable

Returns

Number of elements

BIT

#define BIT

(

n

)

Value:

(1u << (n))

Create a bit mask.

Parameters

n	Bit number (0-15)

Returns

Bitmask with bit n set

u16 flags = BIT(0) | BIT(3);  // 0x0009

Uses 1u (unsigned) so that BIT(15) == 0x8000 holds under cc65816's 16-bit int (since chantier A1, 2026-05-08). With signed 1, 1 << 15 overflows to -32768 on a 16-bit int and compares unequal to the (long-promoted) 0x8000 literal.

CLAMP

#define CLAMP	(		x,
			lo,
			hi )

Value:

(((x) < (lo)) ? (lo) : (((x) > (hi)) ? (hi) : (x)))

Clamp value to range.

Parameters

x	Value to clamp
lo	Minimum value
hi	Maximum value

HI_BYTE

#define HI_BYTE

(

x

)

Value:

((u8)(((x) >> 8) & 0xFF))

Get high byte of 16-bit value.

Parameters

x	16-bit value

Returns

High 8 bits

LO_BYTE

#define LO_BYTE

(

x

)

Value:

((u8)((x) & 0xFF))

Get low byte of 16-bit value.

Parameters

x	16-bit value

Returns

Low 8 bits

MAKE_WORD

#define MAKE_WORD	(		lo,
			hi )

Value:

((u16)(((u8)(hi) << 8) | (u8)(lo)))

Combine two bytes into 16-bit value.

Parameters

lo	Low byte
hi	High byte

Returns

16-bit value

MAX

#define MAX	(		a,
			b )

Value:

(((a) > (b)) ? (a) : (b))

Get maximum of two values.

MIN

#define MIN	(		a,
			b )

Value:

(((a) < (b)) ? (a) : (b))

Get minimum of two values.

NULL

#define NULL   ((void*)0)

Null pointer constant.