StandardLibrary

Status of the support of the OpenCL Standard Library

Source: OpenCL 1.2 Reference Pages, section OpenCL Compiler -> Built-in Functions.

Async Copy and Prefetch Functions

Function	Implementation	Remarks
async_work_group_copy	read/write of DMA block	only executed by the first work-item
async_work_group_strided_copy	per-item copy	only executed by the first work-item
wait_group_events	barrier	other work-items wait for the first one to finish
prefetch	no-op

Common Functions

Function	Implementation	Remarks
clamp	fmin(fmax(a,min), max)
degrees	fmul(a, 180/PI)
max	fmax(a, b)
min	fmin(a, b)
mix	fadd(x, fmul(fsub(y, x), a))
radians	fmul(a, PI/180)
sign	a > 0 ? 1.0 : a <= 0 ? -1.0 : 0.0
smoothstep	see reference	check for improvement
step	a < edge ? 0.0 : 1.0

Explicit Memory Fence Functions

Function	Implementation	Remarks
mem_fence	no-op	memory-access will already be committed immediately
read_mem_fence	no-op	memory-access will already be committed immediately
write_mem_fence	no-op	memory-access will already be committed immediately

Geometric Functions

Function	Implementation	Remarks
cross	a x b
dot	a · b
distance	length(fsub(a,b))
length	sqrt(dot(a,a))
normalize	fdiv(a, sqrt(dot(a,a)))
fast_distance	fast_length(fsub(a,b))
fast_length	half_sqrt(dot(a,a))
fast_normalize	fmul(a, half_rsqrt(dot(a,a)))

Image Functions

Function	Implementation	Remarks
read_imagef	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array, with and without sampler
read_imagei	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array, with and without sampler
read_imageui	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array, with and without sampler
write_imagef	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array
write_imagei	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array
write_imageui	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array
get_image_width	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array
get_image_height	not supported	all versions, int and float coordinates, 1D, 2D and 3D, single and array
get_image_depth	not supported
get_image_channel_data_type	not supported	all versions
get_image_channel_order	not supported	all versions
get_image_dim	not supported	all versions
get_image_array_size	not supported	all versions

Integer Functions

Function	Implementation	Remarks
abs	max(a, -a)
abs_diff	see pocl
add_sat	clamp(add(a, b), type_min, type_max)
clamp	min(max(a, min), max)
clz	clz(a)
hadd	add(shr(add(a,b),1), carry-bit)
mad24	add(mul24(a, b), c)
mad_hi	add(mul_hi(a, b), c)
mad_sat	clamp(add(mul(a, b), c), t_min, t_max)
max	max(a, b)	only signed
min	min(a, b)	only signed
mul24	mul24(a, b)
mul_hi	via mul24
popcount	Brian Kernighan's way	see source
rhadd	add(shr(add(a,b,1),1), carry-bit)
rotate	ror(a, sub(32, b))
sub_sat	clamp(sub(a, b), type_min, type_max)
upsample	or(shl(hi, width), lo)

Math Functions

Function	Implementation	Remarks
acos	fsub(M_PI/2.0f, asin(a))
acosh	via logarithm
acospi	acos(fmul(a, M_PI))
asin	Taylor-series
asinh	Taylor-series
asinpi	asin(fmul(a, M_PI))
atan	Taylor-series
atan2	atan(fdiv(a,b))
atanh	Taylor-series
atanpi	atan(fmul(a, M_PI))
atan2pi	atanpi(fdiv(a,b))
cbrt	pow(a, 1/3f)
ceil
copysign	and(a, or(b, NAN))
cos	Taylor-series	only for -PI to PI
cosh	Taylor-series
cospi	cos(fmul(a, M_PI))
half_cos	cos(a)
native_cos	cos(a)
erf	numeric approximation	see souce
erfc	fsub(1, erf(a))
exp	exp2(fmul(a, M_LOG2E))
half_exp	native_exp(a)	SFU seems to be exact enough
native_exp	native_exp2(fmul(a, M_LOG2E))
exp2	exp10(fmul(a, M_LN2F))
half_exp2	native_exp2(a)	SFU seems to be exact enough
native_exp2	SFU_EXP2(a)
exp10	exp2(fmul(a, M_LOG210))
half_exp10	native_exp10(a)	SFU seems to be exact enough
native_exp10	native_exp2(fmul(a, M_LOG210))
expm1	fsub(exp(a), 1)
fabs	fmaxabs(a, a)
fdim	a>b ? fsub(a,b) : 0
floor
fma	fadd(fmul(a, b), c)	does not heed rounding
fmax	fmax(a, b)
fmin	fmin(a, b)
fmod	see reference	fsub(x, fmul(y, trunc(fdiv(x,y))))
fract	see reference	fmin(a - floor(a), 0x1.fffffep - 1f ), *b = floor(a)
frexp	via ilogb and ldexp
hypot	sqrt(fadd(fmul(a, a), fmul(b, b)))	no special over-/underflow handling
ilogb	and(shr(a, 23), 0xFF)
ldexp	fmul(a, i2f(shl(1, and(b, 31))))	a * 2 ^ b
lgamma		see Numerical Recipes in C, chapter 6.1
lgamma_r	via lgamma
log	fmul(log2(a), 1.0/M_LOG2E)
half_log	native_log(a)	SFU seems to be exact enough
native_log	fmul(native_log2(a), 1/M_LOG2E)
log2	iterative approximation
half_log2	native_log2(a)	SFU seems to be exact enough
native_log2	SFU_LOG2(a)
log10	fmul(log2(a), 1/M_LOG210)
half_log10	native_log10(a)	SFU seems to be exact enough
native_log10	fmul(native_log2(a), 1/M_LOG210)
log1p	log(fadd(1,a))
logb	itof(ilogb(a))
mad	fadd(fmul(a, b), c)
maxmag	see reference
minmag	see reference
modf	sub(a, trunc(a), trunc(a)
nan	and(NaN, a)
nextafter	bitcast_float(bitcast_int(a) + 1))
pow	via powr
pown	fast power	very inefficient for vector-types!
powr	exp(fmul(b, log(a)))
half_powr	powr(a,b)
native_powr	native_exp2(fmul(b, native_log2(a)))
half_recip	native_recip(a)	SFU seems to be exact enough
native_recip	SFU_RECIP(a)
remainder	sub(a, mul(rint(div(a, b)), b))
remquo	via rint and bit-twiddling
rint
round
rootn	pow(a, fdiv(1, itof(b)))	Newton-Verfahren
rsqrt	fdiv(1, sqrt(a))
half_rsqrt	native_rsqrt(a)	SFU seems to be exact enough
native_rsqrt	SFU_RSQRT(a)
sin	Taylor-series	only for -PI to PI
half_sin	sin(a)
native_sin	sin(a)
sincos	(*b = cos(a), sin(a))
sinh	Taylor-series
sinpi	sin(fmul(a, M_PI))
sqrt	Taylor-series
half_sqrt	sqrt(a)
native_sqrt	SFU_RECIP(SFU_RSQRT(a))
tan	Taylor-series
half_tan	tan(a)
native_tan	tan(a)
tanh	Taylor-series
tanpi	tan(fmul(a, M_PI))
tgamma	exp(lgamma(a))
trunc

Misc. Vector Functions

Function	Implementation	Remarks
shuffle	shuffle2(a, a, b)
shuffle2	via intrinsics	uses vector-rotations
vec_step	compiler-intrinsic

Relational Functions

Function	Implementation	Remarks
isequal	xor(a, b) == 0	true = 1 for scalar and -1 for vectors
isnotequal	xor(a, b) != 0	true = 1 for scalar and -1 for vectors
isgreater	xor(fmin(a, b), a) != 0	true = 1 for scalar and -1 for vectors
isgreaterequal	xor(fmax(a, b), a) == 0	true = 1 for scalar and -1 for vectors
isless	xor(fmax(a, b), a) != 0	true = 1 for scalar and -1 for vectors
islessequal	xor(fmin(a, b), a) == 0	true = 1 for scalar and -1 for vectors
islessgreater	or((x < y), (x > y))	true = 1 for scalar and -1 for vectors
isfinite	xor(and(a, INF), INF) != 0	true = 1 for scalar and -1 for vectors
isinf	xor(and(a, INF), INF) == 0	true = 1 for scalar and -1 for vectors
isnan	xor(and(a, NAN), NAN) == 0	true = 1 for scalar and -1 for vectors
isnormal	check for denormal value
isordered	isequal(a, a) && isequal(b, b)
isunordered	isnan(a) || isnan(b)
signbit	shr(a, 31) / asr(a, 31)	arithmetic shift for vector-type
any	see reference
all	see reference
bitselect	or(and(not(c), a), and(c, b))
select	msb(c) ? b : a

Synchronization Function

Function	Implementation	Remarks
barrier		via semaphores per work-item

Vector Data Load and Store Functions

Function	Implementation	Remarks
vloadn	load(add(b, mul(a, vector-size))	(a * vector-count + b)*
vload_half	not supported
vload_halfn	not supported
vloada_halfn	not supported
vstoren	store(add(c, mul(b, vector-size), a)	*(b * vector-count + c) = a
vstore_half	not supported
vstore_halfn	not supported
vstorea_halfn	not supported

Work-Item Functions

Function	Implementation	Remarks
get_global_id	register-read	passed via UNIFORM
get_global_size	register-read	passed via UNIFORM
get_global_offset	register-read	passed via UNIFORM
get_local_id	register-read	passed via UNIFORM
get_local_size	register-read	passed via UNIFORM
get_num_groups	register-read	passed via UNIFORM
get_group_id	register-read	passed via UNIFORM
get_work_dim	register-read	passed via UNIFORM

Atomic Functions

Function	Implementation	Remarks
atomic_add	old = *p, *p = add(old, val)	enclosed in global mutex-lock
atomic_sub	old = *p, *p = sub(old, val)	enclosed in global mutex-lock
atomic_xchg	old = *p, *p = val	enclosed in global mutex-lock
atomic_inc	old = *p, *p = add(old, 1)	enclosed in global mutex-lock
atomic_dec	old = *p, *p = sub(old, 1)	enclosed in global mutex-lock
atomic_cmpxchg	old = *p, tmp = xor(old,cmp), *p = val (if 0)	enclosed in global mutex-lock
atomic_min	old = *p, *p = min(old, val)	enclosed in global mutex-lock
atomic_max	old = *p, *p = max(old, val)	enclosed in global mutex-lock
atomic_and	old = *p, *p = and(old, val)	enclosed in global mutex-lock
atomic_or	old = *p, *p = or(old, val)	enclosed in global mutex-lock
atomic_xor	old = *p, *p = xor(old, val)	enclosed in global mutex-lock

printF

TODO OpenCL 1.2 pages 286+