Quadruple Precision Math Library reference
Table of contents
- Introduction
- Data types
- Convenience macros and constants
- Conversion and output functions
- Comparison functions
- Math functions
- Tutorial
Introduction
As of version 3.6, SLEEF includes a quad-precision math library. This library includes various functions for computing with IEEE 754 quadruple-precision(QP) floating-point numbers. If the compiler natively supports IEEE 754 QP FP type, numbers in this natively supported QP data type can be directly passed to the library functions. Otherwise, the library defines a data type for retaining numbers in IEEE 754 QP data type.
Many of the functions are fully vectorized to maximize the throughput of computation. For these functions, two vector registers are combined to retain a vector of QP FP numbers, where one of these registers holds the upper part of QP numbers, and the other register holds the lower part. Dedicated functions are provided to load to or store from variables in vector QP data types.
Data types
Sleef_quad
Sleef_quad is a data type for retaining a single QP FP number. If the compiler natively supports IEEE 754 quad precision FP type, then Sleef_quad is an alias of that data type.
typedef __float128 Sleef_quad;
typedef long double Sleef_quad; // On AArch64 and System/390 systems
Otherwise, the library defines a 128-bit data type for retaining a number in IEEE 754 QP data format.
Convenience function, macro and constants
sleef_q
Function to define any QP FP constant
#include <sleefquad.h>
Sleef_quad sleef_q (int64_t upper, uint64_t lower, int e);
This is a function for defining any QP FP constant. This function can be used to represent a QP FP constant on compilers without support for a QP FP data type. This function is small and thus the code is likely be optimized so that the immediate QP FP value is available at runtime. You can convert any QP FP value to this representation using qutil utility program.
SLEEF_QUAD_C
Macro for appending the correct suffix to a QP FP literal
#include <sleefquad.h>
Sleef_quad SLEEF_QUAD_C (literal);
This is a macro for appending the correct suffix to a QP FP literal. The data type for representing a QP FP number is not available on all systems, and the data type differs between architectures. This macro can be used to append the correct suffix regardless of the architecture. This macro is defined only if the compiler supports a data type for representing a QP FP number.
Below is the table of QP constants defined in sleefquad.h. These are also defined in the inline headers. These constants are defined as QP literals if the compiler supports them. Otherwise, they are defined with sleef_q function.
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Conversion and output functions
Sleef_strtoq
convert ASCII string to QP FP number
#include <sleefquad.h>
Sleef_quad Sleef_strtoq(const char * str, char ** endptr);
Link with -lsleefquad.
This is a QP version of the strtod function. It converts the given string to a QP FP number. It supports converting from both decimal and hexadecimal numbers.
Sleef_vprintf
Sleef_vfprintf
Sleef_vsnprintf
Format various data into string and output
#include <sleefquad.h>
int Sleef_printf(const char * fmt, ... );
int Sleef_fprintf(FILE * fp, const char * fmt, ... );
int Sleef_snprintf(char * str, size_t size, const char * fmt, ... );
int Sleef_vprintf(const char * fmt, va_list ap);
int Sleef_vfprintf(FILE * fp, const char * fmt, va_list ap);
int Sleef_vsnprintf(char * str, size_t size, const char * fmt, va_list ap);
Link with -lsleefquad.
These functions are equivalent to the corresponding printf functions in the C standard, except for the following extensions. These functions support converting from QP FP numbers using Q and P modifiers with a, e, f and g conversions. With Q modifier, an immediate QP FP value can be passed to these functions, while a QP FP value can be passed via a pointer with P modifier. These functions only supports the format strings defined in the C standard. Beware of this bug when you use this function with clang. These functions are neither thread safe nor atomic.
Sleef_unregisterPrintfHook
Register and unregister C library hooks to printf family funcions in the GNU C Library
#include <sleefquad.h>
void Sleef_registerPrintfHook( void );
void Sleef_unregisterPrintfHook( void );
Link with -lsleefquad.
These functions are defined only on systems with Glibc. Glibc has a functionality for installing C library hooks to extend conversion capability of its printf-familiy functions. Sleef_registerPrintfHook installs C library hooks to add support for the Q and P modifiers. Sleef_unregisterPrintfHook uninstalls the C library hooks.
Sleef_cast_to_doubleq1
Sleef_cast_to_doubleq1_purec
Sleef_cast_to_doubleq1_purecfma
Convert QP number to double-precision number
#include <sleefquad.h>
double Sleef_cast_to_doubleq1(Sleef_quad a);
double Sleef_cast_to_doubleq1_purec(Sleef_quad a);
double Sleef_cast_to_doubleq1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions convert a QP FP value to a double-precision value.
Sleef_cast_from_doubleq1
Sleef_cast_from_doubleq1_purec
Sleef_cast_from_doubleq1_purecfma
Convert double-precision number to QP number
#include <sleefquad.h>
Sleef_quad Sleef_cast_from_doubleq1(double a);
Sleef_quad Sleef_cast_from_doubleq1_purec(double a);
Sleef_quad Sleef_cast_from_doubleq1_purecfma(double a);
Link with -lsleefquad.
These functions convert a double-precision value to a QP FP value.
Sleef_cast_to_int64q1
Sleef_cast_to_int64q1_purec
Sleef_cast_to_int64q1_purecfma
Convert QP number to 64-bit signed integer
#include <sleefquad.h>
int64_t Sleef_cast_to_int64q1(Sleef_quad a);
int64_t Sleef_cast_to_int64q1_purec(Sleef_quad a);
int64_t Sleef_cast_to_int64q1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions convert a QP FP value to a 64-bit signed integer.
Sleef_cast_from_int64q1
Sleef_cast_from_int64q1_purec
Sleef_cast_from_int64q1_purecfma
Convert 64-bit signed integer to QP number
#include <sleefquad.h>
Sleef_quad Sleef_cast_from_int64q1(int64_t a);
Sleef_quad Sleef_cast_from_int64q1_purec(int64_t a);
Sleef_quad Sleef_cast_from_int64q1_purecfma(int64_t a);
Link with -lsleefquad.
These functions convert a 64-bit signed integer to a QP FP value.
Sleef_cast_to_uint64q1
Sleef_cast_to_uint64q1_purec
Sleef_cast_to_uint64q1_purecfma
Convert QP number to 64-bit unsigned integer
#include <sleefquad.h>
uint64_t Sleef_cast_to_uint64q1(Sleef_quad a);
uint64_t Sleef_cast_to_uint64q1_purec(Sleef_quad a);
uint64_t Sleef_cast_to_uint64q1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions convert a QP FP value to a 64-bit signed integer.
Sleef_cast_from_uint64q1
Sleef_cast_from_uint64q1_purec
Sleef_cast_from_uint64q1_purecfma
Convert 64-bit unsigned integer to QP number
#include <sleefquad.h>
Sleef_quad Sleef_cast_from_uint64q1(uint64_t a);
Sleef_quad Sleef_cast_from_uint64q1_purec(uint64_t a);
Sleef_quad Sleef_cast_from_uint64q1_purecfma(uint64_t a);
Link with -lsleefquad.
These functions convert a 64-bit unsigned integer to a QP FP value.
Comparison functions
#include <sleefquad.h>
int32_t Sleef_icmpltq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpleq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpgtq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpgeq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpeqq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpneq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpltq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpleq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpgtq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpgeq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpeqq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpneq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpltq1_purecfma(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpleq1_purecfma(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpgtq1_purecfma(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpgeq1_purecfma(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpeqq1_purecfma(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpneq1_purecfma(Sleef_quad a, Sleef_quad b);
Link with -lsleefquad.
These functions compare two QP FP values. The lt, le, gt, ge, eq and ne functions return 1 if and only if a is less than, less or equal, greather than, greater or equal, equal and not equal to b, respectively. Otherwise, 0 is returned.
Sleef_icmpq1
Sleef_icmpq1_purec
Sleef_icmpq1_purecfma
QP comparison
#include <sleefquad.h>
int32_t Sleef_icmpq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_icmpq1_purecfma(Sleef_quad a, Sleef_quad b);
Link with -lsleefquad.
These functions compare two QP FP values. If a is greater than b, they return 1. If a is less than b, they return -1. Otherwise, they return 0. If either argument is NaN, they return 0.
Sleef_iunordq1
Sleef_iunordq1_purec
Sleef_iunordq1_purecfma
Check orderedness
#include <sleefquad.h>
int32_t Sleef_iunordq1(Sleef_quad a, Sleef_quad b);
int32_t Sleef_iunordq1_purec(Sleef_quad a, Sleef_quad b);
int32_t Sleef_iunordq1_purecfma(Sleef_quad a, Sleef_quad b);
Link with -lsleefquad.
These functions return 1 if either argument is NaN, otherwise 0.
Math functions
Basic Arithmetic
#include <sleefquad.h>
Sleef_quad Sleef_addq1_u05(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_subq1_u05(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_mulq1_u05(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_divq1_u05(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_negq1(Sleef_quad a);
Sleef_quad Sleef_addq1_u05purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_subq1_u05purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_mulq1_u05purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_divq1_u05purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_negq1_purec(Sleef_quad a);
Sleef_quad Sleef_addq1_u05purecfma(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_subq1_u05purecfma(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_mulq1_u05purecfma(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_divq1_u05purecfma(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_negq1_purec(Sleef_quad a);
Link with -lsleefquad.
The add, sub, mul and div functions perform addition, subtraction, multiplication and division of two QP FP values. The error bound of these functions are 0.5000000001 ULP. The neg functions return -a.
Sleef_sqrtq1_u05
Sleef_sqrtq1_u05purec
Sleef_sqrtq1_u05purecfma
square root functions
#include <sleefquad.h>
Sleef_quad Sleef_sqrtq1_u05(Sleef_quad a);
Sleef_quad Sleef_sqrtq1_u05purec(Sleef_quad a);
Sleef_quad Sleef_sqrtq1_u05purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return nonnegative square root of a value in a. The error bound of the returned value is 0.5000000001 ULP.
Sleef_sinq1_u10
Sleef_sinq1_u10purec
Sleef_sinq1_u10purecfma
sine functions
#include <sleefquad.h>
Sleef_quad Sleef_sinq1_u10(Sleef_quad a);
Sleef_quad Sleef_sinq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_sinq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the sine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_cosq1_u10
Sleef_cosq1_u10purec
Sleef_cosq1_u10purecfma
cosine functions
#include <sleefquad.h>
Sleef_quad Sleef_cosq1_u10(Sleef_quad a);
Sleef_quad Sleef_cosq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_cosq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the cosine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_tanq1_u10
Sleef_tanq1_u10purec
Sleef_tanq1_u10purecfma
tangent functions
#include <sleefquad.h>
Sleef_quad Sleef_tanq1_u10(Sleef_quad a);
Sleef_quad Sleef_tanq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_tanq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the tangent function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_asinq1_u10
Sleef_asinq1_u10purec
Sleef_asinq1_u10purecfma
arc sine functions
#include <sleefquad.h>
Sleef_quad Sleef_asinq1_u10(Sleef_quad a);
Sleef_quad Sleef_asinq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_asinq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the arc sine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_acosq1_u10
Sleef_acosq1_u10purec
Sleef_acosq1_u10purecfma
arc cosine functions
#include <sleefquad.h>
Sleef_quad Sleef_acosq1_u10(Sleef_quad a);
Sleef_quad Sleef_acosq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_acosq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the arc cosine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_atanq1_u10
Sleef_atanq1_u10purec
Sleef_atanq1_u10purecfma
arc tangent functions
#include <sleefquad.h>
Sleef_quad Sleef_atanq1_u10(Sleef_quad a);
Sleef_quad Sleef_atanq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_atanq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the arc tangent function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_atan2q1_u10
Sleef_atan2q1_u10purec
Sleef_atan2q1_u10purecfma
arc tangent functions of two variables
#include <sleefquad.h>
Sleef_quad Sleef_atan2q1_u10(Sleef_quad y, Sleef_quad x);
Sleef_quad Sleef_atan2q1_u10purec(Sleef_quad y, Sleef_quad x);
Sleef_quad Sleef_atan2q1_u10purecfma(Sleef_quad y, Sleef_quad x);
Link with -lsleefquad.
These functions evaluate the arc tangent function of ( y / x ). The quadrant of the result is determined according to the signs of x and y. The error bound of the returned value is 1.0 ULP.
Sleef_expq1_u10
Sleef_expq1_u10purec
Sleef_expq1_u10purecfma
base-e exponential functions
#include <sleefquad.h>
Sleef_quad Sleef_expq1_u10(Sleef_quad a);
Sleef_quad Sleef_expq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_expq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the value of e raised to a. The error bound of the returned value is 1.0 ULP.
Sleef_exp2q1_u10
Sleef_exp2q1_u10purec
Sleef_exp2q1_u10purecfma
base-2 exponential functions
#include <sleefquad.h>
Sleef_quad Sleef_exp2q1_u10(Sleef_quad a);
Sleef_quad Sleef_exp2q1_u10purec(Sleef_quad a);
Sleef_quad Sleef_exp2q1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return 2 raised to a. The error bound of the returned value is 1.0 ULP.
Sleef_exp10q1_u10
Sleef_exp10q1_u10purec
Sleef_exp10q1_u10purecfma
base-10 exponentail
#include <sleefquad.h>
Sleef_quad Sleef_exp10q1_u10(Sleef_quad a);
Sleef_quad Sleef_exp10q1_u10purec(Sleef_quad a);
Sleef_quad Sleef_exp10q1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return 10 raised to a. The error bound of the returned value is 1.0 ULP.
Sleef_expm1q1_u10
Sleef_expm1q1_u10purec
Sleef_expm1q1_u10purecfma
base-e exponential functions minus 1
#include <sleefquad.h>
Sleef_quad Sleef_expm1q1_u10(Sleef_quad a);
Sleef_quad Sleef_expm1q1_u10purec(Sleef_quad a);
Sleef_quad Sleef_expm1q1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the value one less than e raised to a. The error bound of the returned value is 1.0 ULP.
Sleef_logq1_u10
Sleef_logq1_u10purec
Sleef_logq1_u10purecfma
natural logarithmic functions
#include <sleefquad.h>
Sleef_quad Sleef_logq1_u10(Sleef_quad a);
Sleef_quad Sleef_logq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_logq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the natural logarithm of a. The error bound of the returned value is 1.0 ULP.
Sleef_log2q1_u10
Sleef_log2q1_u10purec
Sleef_log2q1_u10purecfma
base-2 logarithmic functions
#include <sleefquad.h>
Sleef_quad Sleef_log2q1_u10(Sleef_quad a);
Sleef_quad Sleef_log2q1_u10purec(Sleef_quad a);
Sleef_quad Sleef_log2q1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the base-2 logarithm of a. The error bound of the returned value is 1.0 ULP.
Sleef_log10q1_u10
Sleef_log10q1_u10purec
Sleef_log10q1_u10purecfma
base-10 logarithmic functions
#include <sleefquad.h>
Sleef_quad Sleef_log10q1_u10(Sleef_quad a);
Sleef_quad Sleef_log10q1_u10purec(Sleef_quad a);
Sleef_quad Sleef_log10q1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the base-10 logarithm of a. The error bound of the returned value is 1.0 ULP.
Sleef_log1pq1_u10
Sleef_log1pq1_u10purec
Sleef_log1pq1_u10purecfma
logarithm of one plus argument
#include <sleefquad.h>
Sleef_quad Sleef_log1pq1_u10(Sleef_quad a);
Sleef_quad Sleef_log1pq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_log1pq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the natural logarithm of (1 + a). The error bound of the returned value is 1.0 ULP.
Sleef_powq1_u10
Sleef_powq1_u10purec
Sleef_powq1_u10purecfma
power functions
#include <sleefquad.h>
Sleef_quad Sleef_powq1_u10(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_powq1_u10purec(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_powq1_u10purecfma(Sleef_quad x, Sleef_quad y);
Link with -lsleefquad.
These functions return the value of x raised to the power of y. The error bound of the returned value is 1.0 ULP.
Sleef_sinhq1_u10
Sleef_sinhq1_u10purec
Sleef_sinhq1_u10purecfma
hyperbolic sine functions
#include <sleefquad.h>
Sleef_quad Sleef_sinhq1_u10(Sleef_quad a);
Sleef_quad Sleef_sinhq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_sinhq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the hyperbolic sine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_coshq1_u10
Sleef_coshq1_u10purec
Sleef_coshq1_u10purecfma
hyperbolic cosine functions
#include <sleefquad.h>
Sleef_quad Sleef_coshq1_u10(Sleef_quad a);
Sleef_quad Sleef_coshq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_coshq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the hyperbolic cosine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_tanhq1_u10
Sleef_tanhq1_u10purec
Sleef_tanhq1_u10purecfma
hyperbolic tangent functions
#include <sleefquad.h>
Sleef_quad Sleef_tanhq1_u10(Sleef_quad a);
Sleef_quad Sleef_tanhq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_tanhq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the hyperbolic tangent function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_asinhq1_u10
Sleef_asinhq1_u10purec
Sleef_asinhq1_u10purecfma
inverse hyperbolic sine functions
#include <sleefquad.h>
Sleef_quad Sleef_asinhq1_u10(Sleef_quad a);
Sleef_quad Sleef_asinhq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_asinhq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the inverse hyperbolic sine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_acoshq1_u10
Sleef_acoshq1_u10purec
Sleef_acoshq1_u10purecfma
inverse hyperbolic cosine functions
#include <sleefquad.h>
Sleef_quad Sleef_acoshq1_u10(Sleef_quad a);
Sleef_quad Sleef_acoshq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_acoshq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the inverse hyperbolic cosine function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_atanhq1_u10
Sleef_atanhq1_u10purec
Sleef_atanhq1_u10purecfma
inverse hyperbolic tangent functions
#include <sleefquad.h>
Sleef_quad Sleef_atanhq1_u10(Sleef_quad a);
Sleef_quad Sleef_atanhq1_u10purec(Sleef_quad a);
Sleef_quad Sleef_atanhq1_u10purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions evaluate the inverse hyperbolic tangent function of a value in a. The error bound of the returned value is 1.0 ULP.
Sleef_truncq1
Sleef_truncq1_purec
Sleef_truncq1_purecfma
round to integer towards zero
#include <sleefquad.h>
Sleef_quad Sleef_truncq1(Sleef_quad a);
Sleef_quad Sleef_truncq1_purec(Sleef_quad a);
Sleef_quad Sleef_truncq1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions round their argument to the integer value, in floating format, nearest to but no larger in magnitude than the argument.
Sleef_floorq1
Sleef_floorq1_purec
Sleef_floorq1_purecfma
round to integer towards minus infinity
#include <sleefquad.h>
Sleef_quad Sleef_floorq1(Sleef_quad a);
Sleef_quad Sleef_floorq1_purec(Sleef_quad a);
Sleef_quad Sleef_floorq1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the largest integer value not greater than a.
Sleef_ceilq1
Sleef_ceilq1_purec
Sleef_ceilq1_purecfma
round to integer towards plus infinity
#include <sleefquad.h>
Sleef_quad Sleef_ceilq1(Sleef_quad a);
Sleef_quad Sleef_ceilq1_purec(Sleef_quad a);
Sleef_quad Sleef_ceilq1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the smallest integer value not less than a.
Sleef_roundq1
Sleef_roundq1_purec
Sleef_roundq1_purecfma
round to integer away from zero
#include <sleefquad.h>
Sleef_quad Sleef_roundq1(Sleef_quad a);
Sleef_quad Sleef_roundq1_purec(Sleef_quad a);
Sleef_quad Sleef_roundq1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions round their argument to the nearest integer value, rounding halfway cases away from zero.
Sleef_rintq1
Sleef_rintq1_purec
Sleef_rintq1_purecfma
round to integer, ties round to even
#include <sleefquad.h>
Sleef_quad Sleef_rintq1(Sleef_quad a);
Sleef_quad Sleef_rintq1_purec(Sleef_quad a);
Sleef_quad Sleef_rintq1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions round their argument to an integer value with the round-to-even method.
Sleef_fabsq1
Sleef_fabsq1_purec
Sleef_fabsq1_purecfma
absolute value
#include <sleefquad.h>
Sleef_quad Sleef_fabsq1(Sleef_quad a);
Sleef_quad Sleef_fabsq1_purec(Sleef_quad a);
Sleef_quad Sleef_fabsq1_purecfma(Sleef_quad a);
Link with -lsleefquad.
These functions return the absolute value of a.
Sleef_copysignq1
Sleef_copysignq1_purec
Sleef_copysignq1_purecfma
copy sign of a number
#include <sleefquad.h>
Sleef_quad Sleef_copysignq1(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_copysignq1_purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_copysignq1_purecfma(Sleef_quad a, Sleef_quad b);
Link with -lsleefquad.
These functions return a value with the magnitude of a and the sign of b.
Sleef_fmaxq1
Sleef_fmaxq1_purec
Sleef_fmaxq1_purecfma
maximum of two numbers
#include <sleefquad.h>
Sleef_quad Sleef_fmaxq1(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_fmaxq1_purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_fmaxq1_purecfma(Sleef_quad a, Sleef_quad b);
Link with -lsleefquad.
These functions return the larger value of a and b.
Sleef_fminq1
Sleef_fminq1_purec
Sleef_fminq1_purecfma
minimum of two numbers
#include <sleefquad.h>
Sleef_quad Sleef_fminq1(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_fminq1_purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_fminq1_purecfma(Sleef_quad a, Sleef_quad b);
Link with -lsleefquad.
These functions return the smaller value of a and b.
Sleef_fdimq1_u05
Sleef_fdimq1_u05purec
Sleef_fdimq1_u05purecfma
positive difference
#include <sleefquad.h>
Sleef_quad Sleef_fdimq1_u05(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_fdimq1_u05purec(Sleef_quad a, Sleef_quad b);
Sleef_quad Sleef_fdimq1_u05purecfma(Sleef_quad a, Sleef_quad b);
Link with -lsleefquad.
These functions return the positive difference between a and b. The error bound of these functions are 0.5000000001 ULP.
Sleef_fmodq1
Sleef_fmodq1_purec
Sleef_fmodq1_purecfma
floating point remainder
#include <sleefquad.h>
Sleef_quad Sleef_fmodq1(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_fmodq1_purec(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_fmodq1_purecfma(Sleef_quad x, Sleef_quad y);
Link with -lsleefquad.
These functions return x - n * y, where n is the quotient of x / y, rounded toward zero to an integer.
Sleef_remainderq1
Sleef_remainderq1_purec
Sleef_remainderq1_purecfma
floatint point remainder
#include <sleefquad.h>
Sleef_quad Sleef_remainderq1(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_remainderq1_purec(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_remainderq1_purecfma(Sleef_quad x, Sleef_quad y);
Link with -lsleefquad.
These functions return x - n * y, where n is the quotient of x / y, rounded to an integer with the round-to-even method.
Sleef_frexpq1
Sleef_frexpq1_purec
Sleef_frexpq1_purecfma
split a number to fractional and integral components
#include <sleefquad.h>
Sleef_quad Sleef_frexpq1(Sleef_quad a, int * ptr);
Sleef_quad Sleef_frexpq1_purec(Sleef_quad a, int * ptr);
Sleef_quad Sleef_frexpq1_purecfma(Sleef_quad a, int * ptr);
Link with -lsleefquad.
These functions split the argument a into a fraction f and an exponent e, where 0.5 <= f < 1 and a = f * 2^e. The computed exponent e will be stored in *ptr, and the functions return f.
Sleef_modfq1
Sleef_modfq1_purec
Sleef_modfq1_purecfma
break a number into integral and fractional parts
#include <sleefquad.h>
Sleef_quad Sleef_modfq1(Sleef_quad a, Sleef_quad * ptr);
Sleef_quad Sleef_modfq1_purec(Sleef_quad a, Sleef_quad * ptr);
Sleef_quad Sleef_modfq1_purecfma(Sleef_quad a, Sleef_quad * ptr);
Link with -lsleefquad.
These functions split the argument a into an integral part k and a fractional part f, where k and f have the same sign as a. k will be stored in *ptr, and the functions return f.
Sleef_hypotq1_u05
Sleef_hypotq1_u05purec
Sleef_hypotq1_u05purecfma
2D Euclidian distance
#include <sleefquad.h>
Sleef_quad Sleef_hypotq1_u05(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_hypotq1_u05purec(Sleef_quad x, Sleef_quad y);
Sleef_quad Sleef_hypotq1_u05purecfma(Sleef_quad x, Sleef_quad y);
Link with -lsleefquad.
These functions return the square root of the sum of the squares of x and y`. The error bound of these functions are 0.5000000001 ULP.
Sleef_fmaq1_u05
Sleef_fmaq1_u05purec
Sleef_fmaq1_u05purecfma
fused multiply and accumulate
#include <sleefquad.h>
Sleef_quad Sleef_fmaq1_u05(Sleef_quad x, Sleef_quad y, Sleef_quad z);
Sleef_quad Sleef_fmaq1_u05purec(Sleef_quad x, Sleef_quad y, Sleef_quad z);
Sleef_quad Sleef_fmaq1_u05purecfma(Sleef_quad x, Sleef_quad y, Sleef_quad z);
Link with -lsleefquad.
These functions return x * y + z with a single rounding. The error bound of these functions are 0.5000000001 ULP.
Sleef_ldexpq1
Sleef_ldexpq1_purec
Sleef_ldexpq1_purecfma
multiply by integral power of 2
#include <sleefquad.h>
Sleef_quad Sleef_ldexpq1(Sleef_quad x, int e);
Sleef_quad Sleef_ldexpq1_purec(Sleef_quad x, int e);
Sleef_quad Sleef_ldexpq1_purecfma(Sleef_quad x, int e);
Link with -lsleefquad.
These functions return x * 2^e.
Sleef_ilogbq1
Sleef_ilogbq1_purec
Sleef_ilogbq1_purecfma
integer exponent of an FP number
#include <sleefquad.h>
int Sleef_ilogbq1(Sleef_quad x);
int Sleef_ilogbq1_purec(Sleef_quad x);
int Sleef_ilogbq1_purecfma(Sleef_quad x);
Link with -lsleefquad.
These functions return the exponent of x. If x is zero, infinite and a NaN, they return SLEEF_FP_ILOGB0, INT_MAX and SLEEF_FP_ILOGBNAN`, respectively.
Tutorial
I would like to show an example of how the vectorized QP functions can be used. Below is a source code for computing π with Machin’s formula on x86 GNU systems. This formula has two terms with arc tangent which can be independently calculated. In this example, these two terms are computed using vector functions. __float128 data type is defined on x86, and you can use literals in this type to initialize the variables. Variables q0, q1, q2 and q3 retain two QP FP values each. At line 5, 8 and 11, QP values in arrays are loaded into these variables with Sleef_loadq2_sse2 function. Vector operations are carried out from line 14 to 16, and then each element of the vector variable q3 is extracted with Sleef_getq2_sse2 function and subtracted to obtain the result at line 18. Note that the QP subtract function in the standard library is called to do this subtraction. This result is output to the console using Sleef_printf function at line 22. Note that this source code can be built with clang, on which libquadmath is not available.
#include <sleefquad.h>
int main(int argc, char **argv) {
__float128 a0[] = { 5, 239 };
Sleef_quadx2 q0 = Sleef_loadq2_sse2(a0);
__float128 a1[] = { 1, 1 };
Sleef_quadx2 q1 = Sleef_loadq2_sse2(a1);
__float128 a2[] = { 16, 4 };
Sleef_quadx2 q2 = Sleef_loadq2_sse2(a2);
Sleef_quadx2 q3;
q3 = Sleef_divq2_u05sse2(q1, q0);
q3 = Sleef_atanq2_u10sse2(q3);
q3 = Sleef_mulq2_u05sse2(q3, q2);
__float128 pi = Sleef_getq2_sse2(q3, 0) - Sleef_getq2_sse2(q3, 1);
Sleef_printf("%.40Pg\n", &pi);
}
Fig. 4.1: Example source code for x86 computers
__float128 data type is not defined on MSVC, and thus we cannot use literals of this type to initialize QP variables. Sleef provides various conversion functions for this purpose. In the following source code, Sleef_cast_from_doubleq1_purec function is used to initialize q0 from line 4 to 5. Sleef_strtoq function is used to initialize q1 at line 7. Here, Sleef_splatq2_sse2 function is a function for setting the specified QP FP value to all elements in a vector. Obtaining QP FP constants by calling these functions may waste some CPU time. From line 9 and 12, sleef_q function is used to intialize q2. sleef_q is a function for defining a QP FP constant. You can convert any QP FP value to this representation using qutil utility program. At line 20, Sleef_subq1_u05purec function is used to subtract a scalar value from another to obtain the result.
#include <sleefquad.h>
int main(int argc, char **argv) {
Sleef_quad a0[] = { Sleef_cast_from_doubleq1_purec(5), Sleef_cast_from_doubleq1_purec(239) };
Sleef_quadx2 q0 = Sleef_loadq2_sse2(a0);
Sleef_quadx2 q1 = Sleef_splatq2_sse2(Sleef_strtoq("1.0", NULL));
Sleef_quadx2 q2 = Sleef_loadq2_sse2((Sleef_quad[]) {
sleef_q(+0x1000000000000LL, 0x0000000000000000ULL, 4), // 16.0
sleef_q(+0x1000000000000LL, 0x0000000000000000ULL, 2), // 4.0
});
Sleef_quadx2 q3;
q3 = Sleef_divq2_u05sse2(q1, q0);
q3 = Sleef_atanq2_u10sse2(q3);
q3 = Sleef_mulq2_u05sse2(q3, q2);
Sleef_quad pi = Sleef_subq1_u05purec(Sleef_getq2_sse2(q3, 0), Sleef_getq2_sse2(q3, 1));
Sleef_printf("%.40Pg\n", &pi);
}
Fig. 4.2: Example source code for MSVC