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Macros | Functions
pico_double
Runtime Infrastructure

Optimized double-precision floating point functions. More...

Macros

#define PICO_DOUBLE_HAS_INT32_TO_DOUBLE_CONVERSIONS   1
 Set if int2double and uint2double are available.
 
#define PICO_DOUBLE_HAS_INT64_TO_DOUBLE_CONVERSIONS   1
 Set if int642double and uint642double are available.
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_INT32_Z_CONVERSIONS   1
 Set if double2int_z and double2uint_z are available (rounding towards zero)
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_INT64_Z_CONVERSIONS   1
 Set if double2int64_z and double2uint64_z are available (rounding towards zero)
 
#define PICO_DOUBLE_HAS_FIX32_TO_DOUBLE_CONVERSIONS   1
 Set if fix2double and ufix2double are available.
 
#define PICO_DOUBLE_HAS_FIX64_TO_DOUBLE_CONVERSIONS   1
 Set if fix642double and ufix642double are available.
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_FIX32_Z_CONVERSIONS   1
 Set if double2fix_z and double2ufix_z are available (rounding towards zero)
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_FIX64_Z_CONVERSIONS   1
 Set if double2fix64_z and double2ufix64_z are available (rounding towards zero)
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_INT32_M_CONVERSIONS   1
 Set if double2int and double2uint are available (rounding towards -Infinity)
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_INT64_M_CONVERSIONS   1
 Set if double2int64 and double2uint64 are available (rounding towards -Infinity)
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_FIX32_M_CONVERSIONS   1
 Set if double2fix and double2ufix are available (rounding towards -Infinity)
 
#define PICO_DOUBLE_HAS_DOUBLE_TO_FIX64_M_CONVERSIONS   1
 Set if double2fix64 and double2ufix64 are available (rounding towards -Infinity)
 
#define PICO_DOUBLE_HAS_DDIV_FAST   1
 Set if ddiv_fast is available.
 
#define PICO_DOUBLE_HAS_SQRT_FAST   1
 Set if sqrt_fast is available.
 
#define PICO_DOUBLE_HAS_FMA_FAST   1
 Set if fma_fast is available.
 
#define PICO_DOUBLE_HAS_POWINT   1
 Set if powint is available.
 

Functions

double int2double (int32_t i)
 Convert a signed 32-bit integer to the nearest double.
 
double uint2double (uint32_t u)
 Convert an unsigned 32-bit integer to the nearest double.
 
double int642double (int64_t i)
 Convert a signed 64-bit integer to the nearest double.
 
double uint642double (uint64_t u)
 Convert an unsigned 64-bit integer to the nearest double.
 
int32_t double2int_z (double d)
 Convert a double to a signed 32-bit integer, rounding towards zero. On Arm this conversion is saturating (to INT32_MAX/INT32_MIN) for out of range input except when using pico_double compiler
 
uint32_t double2uint_z (double d)
 Convert a double to an unsigned 32-bit integer, rounding towards zero On Arm this conversion is saturating (to UINT32_MAX/UINT32_MIN) for out of range input except when using pico_double compiler
 
int64_t double2int64_z (double d)
 Convert a double to a signed 64-bit integer, rounding towards zero. On Arm this conversion is saturating (to INT64_MAX/INT64_MIN) for out of range input except when using pico_double compiler
 
uint64_t double2uint64_z (double d)
 Convert a double to an unsigned 64-bit integer, rounding towards zero. On Arm this conversion is saturating (to UINT64_MAX/UINT64_MIN) for out of range input except when using pico_double compiler
 
double fix2double (int32_t m, int e)
 Convert a signed 32-bit fixed-point integer with the given number of fractional bits to the nearest double Out of range inputs will convert to +/- Infinity.
 
double ufix2double (uint32_t m, int e)
 Convert an unsigned 32-bit fixed-point integer with the given number of fractional bits to the nearest double Out of range inputs will convert to +Infinity.
 
double fix642double (int64_t m, int e)
 Convert a signed 64-bit fixed-point integer with the given number of fractional bits to the nearest double Out of range inputs will convert to +/- Infinity.
 
double ufix642double (uint64_t m, int e)
 Convert an unsigned 64-bit fixed-point integer with the given number of fractional bits to the nearest double Out of range inputs will convert to +Infinity.
 
int32_t double2fix_z (double d, int e)
 Convert a double to a signed 32-bit fixed-point integer with the given number of fractional bits, rounding towards zero. On Arm this conversion is saturating (to INT32_MAX/INT32_MIN) for out of range input except when using pico_double compiler
 
uint32_t double2ufix_z (double d, int e)
 Convert a double to an unsigned 32-bit fixed-point integer with the given number of fractional bits, rounding towards zero. This conversion is saturating (to UINT32_MAX/UINT32_MIN) for out of range input.
 
int64_t double2fix64_z (double d, int e)
 Convert a double to a signed 64-bit fixed-point integer with the given number of fractional bits, rounding towards zero. On Arm this conversion is saturating (to INT64_MAX/INT64_MIN) for out of range input except when using pico_double compiler
 
uint64_t double2ufix64_z (double d, int e)
 Convert a double to an unsigned 64-bit fixed-point integer with the given number of fractional bits, rounding towards zero. This conversion is saturating (to UINT64_MAX/UINT64_MIN) for out of range input.
 
int32_t double2int (double d)
 Convert a double to a signed 32-bit integer, rounding towards -Infinity. This conversion is saturating (to INT32_MAX/INT32_MIN) for out of range input.
 
uint32_t double2uint (double d)
 Convert a double to an unsigned 32-bit integer, rounding towards -Infinity. This conversion is saturating (to UINT32_MAX/UINT32_MIN) for out of range input.
 
int64_t double2int64 (double d)
 Convert a double to a signed 64-bit integer, rounding towards -Infinity. This conversion is saturating (to INT64_MAX/INT64_MIN) for out of range input.
 
uint64_t double2uint64 (double d)
 Convert a double to an usigned 64-bit integer, rounding towards -Infinity. This conversion is saturating (to UINT64_MAX/UINT64_MIN) for out of range input.
 
int32_t double2fix (double d, int e)
 Convert a double to a signed 32-bit fixed-point integer with the given number of fractional bits, rounding towards -Infinity. This conversion is saturating (to INT32_MAX/INT32_MIN) for out of range input.
 
uint32_t double2ufix (double d, int e)
 Convert a double to an unsigned 32-bit fixed-point integer with the given number of fractional bits, rounding towards -Infinity. This conversion is saturating (to UINT32_MAX/UINT32_MIN) for out of range input.
 
int64_t double2fix64 (double d, int e)
 Convert a double to a signed 64-bit fixed-point integer with the given number of fractional bits, rounding towards -Infinity. This conversion is saturating (to INT64_MAX/INT64_MIN) for out of range input.
 
uint64_t double2ufix64 (double d, int e)
 Convert a double to an unsigned 64-bit fixed-point integer with the given number of fractional bits, rounding towards -Infinity. This conversion is saturating (to UINT64_MAX/UINT64_MIN) for out of range input.
 
double exp10 (double x)
 Evaluate 10.0 to the power of the given value.
 
void sincos (double x, double *sinx, double *cosx)
 Return both the sine and cosine of an angle efficiently.
 
double powint (double x, int32_t y)
 Raise a floating point number to an integer power.
 
double ddiv_fast (double n, double d)
 Perform a fast floating point divide with reduced accuracy.
 
double sqrt_fast (double d)
 Perform a fast floating point square-root with reduced accuracy.
 
double fma_fast (double x, double y, double z)
 Perform a fast (non-fused) multiply-add (x * y + z) with reduced accuracy.
 
double mla (double x, double y, double z)
 Perform a fast multiply-add (x * y + z) with reduced accuracy (not fused multiply-add). This is another name for fma_fast.
 

Detailed Description

Optimized double-precision floating point functions.

An application can take control of the floating point routines used in the application over and above what is provided by the compiler, by depending on the pico_double library. A user might want to do this:

  1. To use optimized software implementations provided by the RP2-series device's bootrom or the SDK
  2. To use optimized combined software/hardware implementations utilizing custom RP2-series hardware for acceleration
  3. To control the amount of C compiler/library code bloat
  4. To make sure no floating point is called at all

The pico_double library comes in three main flavors:

  1. none - all floating point operations cause a panic - no double-precision floating point code is included
  2. compiler - no custom functions are provided; all double-precision floating point is handled by the C compiler/library
  3. pico - the smallest and fastest available for the platform, along with additional functionality (e.g. fixed point conversions) which are detailed below

The user can control which version they want (e.g. pico_double compiler by either setting the CMake global variable PICO_DEFAULT_DOUBLE_IMPL=compiler, or by using the CMake function pico_set_double_implementation(<TARGET> compiler). Note that in the absence of either, pico_double pico is used by default.

On RP2040, pico_double pico uses optimized hand coded implementations from the bootrom and the SDK for both basic double-precision floating point operations and floating point math library functions. These implementations are generally faster and smaller than those provided by the C compiler/library, though they don't support all the features of a fully compliant floating point implementation; they are however usually fine for the majority of cases

On Arm, (replacement) optimized implementations are provided for the following compiler built-ins and math library functions when using pico_double pico:

On Arm, the following additional optimized functions are also provided when using pico_double pico, all of which saturate to the nearest representable value for too large input when converting from floating point types: