4.1 Routines for integer arithmetic
The integer arithmetic routines are used on platforms that don't provide
hardware support for arithmetic operations on some modes.
4.1.1 Arithmetic functions
— Runtime Function: int
__ashlsi3 (
int a, int b)
— Runtime Function: long
__ashldi3 (
long a, int b)
— Runtime Function: long long
__ashlti3 (
long long a, int b)
These functions return the result of shifting a left by b bits.
— Runtime Function: int
__ashrsi3 (
int a, int b)
— Runtime Function: long
__ashrdi3 (
long a, int b)
— Runtime Function: long long
__ashrti3 (
long long a, int b)
These functions return the result of arithmetically shifting a right
by b bits.
— Runtime Function: int
__divsi3 (
int a, int b)
— Runtime Function: long
__divdi3 (
long a, long b)
— Runtime Function: long long
__divti3 (
long long a, long long b)
These functions return the quotient of the signed division of a and
b.
— Runtime Function: int
__lshrsi3 (
int a, int b)
— Runtime Function: long
__lshrdi3 (
long a, int b)
— Runtime Function: long long
__lshrti3 (
long long a, int b)
These functions return the result of logically shifting a right by
b bits.
— Runtime Function: int
__modsi3 (
int a, int b)
— Runtime Function: long
__moddi3 (
long a, long b)
— Runtime Function: long long
__modti3 (
long long a, long long b)
These functions return the remainder of the signed division of a
and b.
— Runtime Function: int
__mulsi3 (
int a, int b)
— Runtime Function: long
__muldi3 (
long a, long b)
— Runtime Function: long long
__multi3 (
long long a, long long b)
These functions return the product of a and b.
— Runtime Function: long
__negdi2 (
long a)
— Runtime Function: long long
__negti2 (
long long a)
These functions return the negation of a.
— Runtime Function: unsigned int
__udivsi3 (
unsigned int a, unsigned int b)
— Runtime Function: unsigned long
__udivdi3 (
unsigned long a, unsigned long b)
— Runtime Function: unsigned long long
__udivti3 (
unsigned long long a, unsigned long long b)
These functions return the quotient of the unsigned division of a
and b.
— Runtime Function: unsigned long
__udivmoddi3 (
unsigned long a, unsigned long b, unsigned long *c)
— Runtime Function: unsigned long long
__udivti3 (
unsigned long long a, unsigned long long b, unsigned long long *c)
These functions calculate both the quotient and remainder of the unsigned
division of a and b. The return value is the quotient, and
the remainder is placed in variable pointed to by c.
— Runtime Function: unsigned int
__umodsi3 (
unsigned int a, unsigned int b)
— Runtime Function: unsigned long
__umoddi3 (
unsigned long a, unsigned long b)
— Runtime Function: unsigned long long
__umodti3 (
unsigned long long a, unsigned long long b)
These functions return the remainder of the unsigned division of a
and b.
4.1.2 Comparison functions
The following functions implement integral comparisons. These functions
implement a low-level compare, upon which the higher level comparison
operators (such as less than and greater than or equal to) can be
constructed. The returned values lie in the range zero to two, to allow
the high-level operators to be implemented by testing the returned
result using either signed or unsigned comparison.
— Runtime Function: int
__cmpdi2 (
long a, long b)
— Runtime Function: int
__cmpti2 (
long long a, long long b)
These functions perform a signed comparison of a and b. If
a is less than b, they return 0; if a is greater than
b, they return 2; and if a and b are equal they return 1.
— Runtime Function: int
__ucmpdi2 (
unsigned long a, unsigned long b)
— Runtime Function: int
__ucmpti2 (
unsigned long long a, unsigned long long b)
These functions perform an unsigned comparison of a and b.
If a is less than b, they return 0; if a is greater than
b, they return 2; and if a and b are equal they return 1.
4.1.3 Trapping arithmetic functions
The following functions implement trapping arithmetic. These functions
call the libc function abort upon signed arithmetic overflow.
— Runtime Function: int
__absvsi2 (
int a)
— Runtime Function: long
__absvdi2 (
long a)
These functions return the absolute value of a.
— Runtime Function: int
__addvsi3 (
int a, int b)
— Runtime Function: long
__addvdi3 (
long a, long b)
These functions return the sum of a and b; that is
a + b.
— Runtime Function: int
__mulvsi3 (
int a, int b)
— Runtime Function: long
__mulvdi3 (
long a, long b)
The functions return the product of a and b; that is
a * b.
— Runtime Function: int
__negvsi2 (
int a)
— Runtime Function: long
__negvdi2 (
long a)
These functions return the negation of a; that is -a.
— Runtime Function: int
__subvsi3 (
int a, int b)
— Runtime Function: long
__subvdi3 (
long a, long b)
These functions return the difference between b and a;
that is a - b.
4.1.4 Bit operations
— Runtime Function: int
__clzsi2 (
int a)
— Runtime Function: int
__clzdi2 (
long a)
— Runtime Function: int
__clzti2 (
long long a)
These functions return the number of leading 0-bits in a, starting
at the most significant bit position. If a is zero, the result is
undefined.
— Runtime Function: int
__ctzsi2 (
int a)
— Runtime Function: int
__ctzdi2 (
long a)
— Runtime Function: int
__ctzti2 (
long long a)
These functions return the number of trailing 0-bits in a, starting
at the least significant bit position. If a is zero, the result is
undefined.
— Runtime Function: int
__ffsdi2 (
long a)
— Runtime Function: int
__ffsti2 (
long long a)
These functions return the index of the least significant 1-bit in a,
or the value zero if a is zero. The least significant bit is index
one.
— Runtime Function: int
__paritysi2 (
int a)
— Runtime Function: int
__paritydi2 (
long a)
— Runtime Function: int
__parityti2 (
long long a)
These functions return the value zero if the number of bits set in
a is even, and the value one otherwise.
— Runtime Function: int
__popcountsi2 (
int a)
— Runtime Function: int
__popcountdi2 (
long a)
— Runtime Function: int
__popcountti2 (
long long a)
These functions return the number of bits set in a.
— Runtime Function: int32_t
__bswapsi2 (
int32_t a)
— Runtime Function: int64_t
__bswapdi2 (
int64_t a)
These functions return the a byteswapped.