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#ifndef ARITHMETIC_H_
#define ARITHMETIC_H_
#include "util.h"
#define ARITHMETIC_ASM_AVR8 1
/* Saturated unsigned addition (32 bit). */
static inline uint32_t add_sat_u32(uint32_t a, uint32_t b)
{
#if ARITHMETIC_ASM_AVR8
__asm__ __volatile__(
"add %A0, %A1 \n"
"adc %B0, %B1 \n"
"adc %C0, %C1 \n"
"adc %D0, %D1 \n"
"brcc 1f \n"
"ldi %A0, 0xFF \n"
"ldi %B0, 0xFF \n"
"ldi %C0, 0xFF \n"
"ldi %D0, 0xFF \n"
"1: \n"
: "+d" (a)
: "d" (b)
);
return a;
#else
uint32_t x = (uint32_t)(a + b);
if (x < a)
return UINT32_MAX;
return x;
#endif
}
#ifdef uint24_t
/* Saturated unsigned addition (24 bit). */
static inline uint24_t add_sat_u24(uint24_t a, uint24_t b)
{
#if ARITHMETIC_ASM_AVR8
__asm__ __volatile__(
"add %A0, %A1 \n"
"adc %B0, %B1 \n"
"adc %C0, %C1 \n"
"brcc 1f \n"
"ldi %A0, 0xFF \n"
"ldi %B0, 0xFF \n"
"ldi %C0, 0xFF \n"
"1: \n"
: "+d" (a)
: "d" (b)
);
return a;
#else
uint24_t x = (uint24_t)(a + b);
if (x < a)
return (uint24_t)0xFFFFFFlu;
return x;
#endif
}
#endif /* uint24_t */
/* Saturated unsigned addition (16 bit). */
static inline uint16_t add_sat_u16(uint16_t a, uint16_t b)
{
#if ARITHMETIC_ASM_AVR8
__asm__ __volatile__(
"add %A0, %A1 \n"
"adc %B0, %B1 \n"
"brcc 1f \n"
"ldi %A0, 0xFF \n"
"ldi %B0, 0xFF \n"
"1: \n"
: "+d" (a)
: "d" (b)
);
return a;
#else
uint16_t x = (uint16_t)(a + b);
if (x < a)
return UINT16_MAX;
return x;
#endif
}
/* Saturated unsigned addition (8 bit). */
static inline uint8_t add_sat_u8(uint8_t a, uint8_t b)
{
#if ARITHMETIC_ASM_AVR8
if (__builtin_constant_p(b) && (b == 1u)) {
__asm__ __volatile__(
"inc %0 \n"
"brne 1f \n"
"com %0 \n"
"1: \n"
: "+r" (a)
: /* none */
);
} else {
__asm__ __volatile__(
"add %0, %1 \n"
"brcc 1f \n"
"ldi %0, 0xFF \n"
"1: \n"
: "+d" (a)
: "d" (b)
);
}
return a;
#else
uint8_t x = (uint8_t)(a + b);
if (x < a)
return UINT8_MAX;
return x;
#endif
}
/* Saturated unsigned subtraction (32 bit). */
static inline uint32_t sub_sat_u32(uint32_t a, uint32_t b)
{
#if ARITHMETIC_ASM_AVR8
__asm__ __volatile__(
"sub %A0, %A1 \n"
"sbc %B0, %B1 \n"
"sbc %C0, %C1 \n"
"sbc %D0, %D1 \n"
"brcc 1f \n"
"clr %A0 \n"
"clr %B0 \n"
"clr %C0 \n"
"clr %D0 \n"
"1: \n"
: "+r" (a)
: "r" (b)
);
return a;
#else
uint32_t x = (uint32_t)(a - b);
if (x > a)
return 0;
return x;
#endif
}
#ifdef uint24_t
/* Saturated unsigned subtraction (24 bit). */
static inline uint24_t sub_sat_u24(uint24_t a, uint24_t b)
{
#if ARITHMETIC_ASM_AVR8
__asm__ __volatile__(
"sub %A0, %A1 \n"
"sbc %B0, %B1 \n"
"sbc %C0, %C1 \n"
"brcc 1f \n"
"clr %A0 \n"
"clr %B0 \n"
"clr %C0 \n"
"1: \n"
: "+r" (a)
: "r" (b)
);
return a;
#else
uint24_t x = (uint24_t)(a - b);
if (x > a)
return 0;
return x;
#endif
}
#endif /* uint24_t */
/* Saturated unsigned subtraction (16 bit). */
static inline uint16_t sub_sat_u16(uint16_t a, uint16_t b)
{
#if ARITHMETIC_ASM_AVR8
if (__builtin_constant_p(b)) {
__asm__ __volatile__(
"sbiw %A0, %A1 \n"
"brcc 1f \n"
"clr %A0 \n"
"clr %B0 \n"
"1: \n"
: "+w" (a)
: "I" (b)
);
} else {
__asm__ __volatile__(
"sub %A0, %A1 \n"
"sbc %B0, %B1 \n"
"brcc 1f \n"
"clr %A0 \n"
"clr %B0 \n"
"1: \n"
: "+r" (a)
: "r" (b)
);
}
return a;
#else
uint16_t x = (uint16_t)(a - b);
if (x > a)
return 0;
return x;
#endif
}
/* Saturated unsigned subtraction (8 bit). */
static inline uint8_t sub_sat_u8(uint8_t a, uint8_t b)
{
#if ARITHMETIC_ASM_AVR8
if (__builtin_constant_p(b)) {
__asm__ __volatile__(
"subi %0, %1 \n"
"brcc 1f \n"
"clr %0 \n"
"1: \n"
: "+d" (a)
: "M" (b)
);
} else {
__asm__ __volatile__(
"sub %0, %1 \n"
"brcc 1f \n"
"clr %0 \n"
"1: \n"
: "+r" (a)
: "r" (b)
);
}
return a;
#else
uint8_t x = (uint8_t)(a - b);
if (x > a)
return 0;
return x;
#endif
}
#endif /* ARITHMETIC_H_ */
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