bcd.h File Reference

#include <types.h>
#include <stdint.h>

Go to the source code of this file.

Macros
#define	BCD_HEX(v)   ((BCD)(v))
#define	MAKE_BCD(v)   BCD_HEX(0x ## v)

Typedefs
typedef uint32_t	BCD

Functions
void	uint2bcd (uint16_t i, BCD *value)
void	bcd_add (BCD *sour, const BCD *value)
void	bcd_sub (BCD *sour, const BCD *value)
uint8_t	bcd2text (const BCD *bcd, uint8_t tile_offset, uint8_t *buffer)

Detailed Description

Support for working with BCD (Binary Coded Decimal)

See the example BCD project for additional details.

Macro Definition Documentation

BCD_HEX

#define BCD_HEX

(

v

)

((BCD)(v))

MAKE_BCD

#define MAKE_BCD

(

v

)

BCD_HEX(0x ## v)

Converts an integer value into BCD format

A maximum of 8 digits may be used

Typedef Documentation

BCD

typedef uint32_t BCD

Function Documentation

uint2bcd()

void uint2bcd	(	uint16_t	i,
		BCD *	value
	)

Converts integer i into BCD format (Binary Coded Decimal)

Parameters

i	Numeric value to convert
value	Pointer to a BCD variable to store the converted result

bcd_add()

void bcd_add	(	BCD *	sour,
		const BCD *	value
	)

Adds two numbers in BCD format: sour += value

Parameters

sour	Pointer to a BCD value to add to (and where the result is stored)
value	Pointer to the BCD value to add to sour

bcd_sub()

void bcd_sub	(	BCD *	sour,
		const BCD *	value
	)

Subtracts two numbers in BCD format: sour -= value

Parameters

sour	Pointer to a BCD value to subtract from (and where the result is stored)
value	Pointer to the BCD value to subtract from sour

bcd2text()

uint8_t bcd2text	(	const BCD *	bcd,
		uint8_t	tile_offset,
		uint8_t *	buffer
	)

Convert a BCD number into an asciiz (null terminated) string and return the length

Parameters

bcd	Pointer to BCD value to convert
tile_offset	Optional per-character offset value to add (use 0 for none)
buffer	Buffer to store the result in

Returns: Length in characters (always 8)

buffer should be large enough to store the converted string (9 bytes: 8 characters + 1 for terminator)

There are a couple different ways to use tile_offset. For example:

• It can be the Index of the Font Tile '0' in VRAM to allow the buffer to be used directly with set_bkg_tiles.
• It can also be set to the ascii value for character '0' so that the buffer is a normal string that can be passed to printf.