[Libclc-dev] [PATCH 7/7] Add vstore_half_rte implementation

[Jeroen Ketema via Libclc-dev]

The comments on this patch set look a bit funny to me (multiline with stars as the left margin, don’t see much of that in LLVM). Otherwise, LGTM, although I cannot possibly comment on the implementations of the rounding functions (I assume these are pretty much standard?).

Jeroen

> On 29 Jan 2018, at 01:07, Jan Vesely via Libclc-dev <libclc-dev at lists.llvm.org> wrote:
> 
> Passes CTS on carrizo
> Signed-off-by: Jan Vesely <jan.vesely at rutgers.edu>
> ---
> generic/include/clc/shared/vstore.h |  2 ++
> generic/lib/shared/vstore.cl        | 45 ++++++++++++++++++++++++++++++++++++-
> 2 files changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/generic/include/clc/shared/vstore.h b/generic/include/clc/shared/vstore.h
> index b510e0a..ebad330 100644
> --- a/generic/include/clc/shared/vstore.h
> +++ b/generic/include/clc/shared/vstore.h
> @@ -40,6 +40,7 @@ _CLC_VECTOR_VSTORE_HALF_PRIM1(float,)
> _CLC_VECTOR_VSTORE_HALF_PRIM1(float, _rtz)
> _CLC_VECTOR_VSTORE_HALF_PRIM1(float, _rtn)
> _CLC_VECTOR_VSTORE_HALF_PRIM1(float, _rtp)
> +_CLC_VECTOR_VSTORE_HALF_PRIM1(float, _rte)
> 
> #ifdef cl_khr_fp64
>   _CLC_VECTOR_VSTORE_PRIM1(double)
> @@ -47,6 +48,7 @@ _CLC_VECTOR_VSTORE_HALF_PRIM1(float, _rtp)
>   _CLC_VECTOR_VSTORE_HALF_PRIM1(double, _rtz)
>   _CLC_VECTOR_VSTORE_HALF_PRIM1(double, _rtn)
>   _CLC_VECTOR_VSTORE_HALF_PRIM1(double, _rtp)
> +  _CLC_VECTOR_VSTORE_HALF_PRIM1(double, _rte)
> #endif
> 
> #ifdef cl_khr_fp16
> diff --git a/generic/lib/shared/vstore.cl b/generic/lib/shared/vstore.cl
> index 2bfb369..c035095 100644
> --- a/generic/lib/shared/vstore.cl
> +++ b/generic/lib/shared/vstore.cl
> @@ -147,6 +147,27 @@ _CLC_DEF _CLC_OVERLOAD float __clc_rtp(float x)
> {
> 	return ((as_uint(x) & 0x80000000) == 0) ? __clc_rti(x) : __clc_rtz(x);
> }
> +_CLC_DEF _CLC_OVERLOAD float __clc_rte(float x)
> +{
> +	/* Mantisa + implicit bit */
> +	const uint mantissa = (as_uint(x) & 0x7fffff) | (1u << 23);
> +	const int exp = (as_uint(x) >> 23 & 0xff) - 127;
> +	int shift = 13;
> +	if (exp < -14) {
> +		/* The default assumes lower 13 bits are rounded,
> +		 * but it might be more for denormals.
> +		 * Shifting beyond last == 0b, and qr == 00b is not necessary */
> +		shift += min(-(exp + 14), 15);
> +	}
> +	int mask = (1 << shift) - 1;
> +	const uint grs = mantissa & mask;
> +	const uint last = mantissa & (1 << shift);
> +	/* IEEE round up rule is: grs > 101b or grs == 100b and last == 1.
> +	 * exp > 15 should round to inf. */
> +	bool roundup = (grs > (1 << (shift - 1))) ||
> +		(grs == (1 << (shift - 1)) && last != 0) || (exp > 15);
> +	return roundup ? __clc_rti(x) : __clc_rtz(x);
> +}
> 
> #ifdef cl_khr_fp64
> _CLC_DEF _CLC_OVERLOAD double __clc_noop(double x)
> @@ -192,13 +213,35 @@ _CLC_DEF _CLC_OVERLOAD double __clc_rtp(double x)
> {
> 	return ((as_ulong(x) & 0x8000000000000000UL) == 0) ? __clc_rti(x) : __clc_rtz(x);
> }
> +_CLC_DEF _CLC_OVERLOAD double __clc_rte(double x)
> +{
> +	/* Mantisa + implicit bit */
> +	const ulong mantissa = (as_ulong(x) & 0xfffffffffffff) | (1UL << 52);
> +	const int exp = (as_ulong(x) >> 52 & 0x7ff) - 1023;
> +	int shift = 42;
> +	if (exp < -14) {
> +		/* The default assumes lower 13 bits are rounded,
> +		 * but it might be more for denormals.
> +		 * Shifting beyond last == 0b, and qr == 00b is not necessary */
> +		shift += min(-(exp + 14), 15);
> +	}
> +	ulong mask = (1UL << shift) - 1UL;
> +	const ulong grs = mantissa & mask;
> +	const ulong last = mantissa & (1UL << shift);
> +	/* IEEE round up rule is: grs > 101b or grs == 100b and last == 1.
> +	 * exp > 15 should round to inf. */
> +	bool roundup = (grs > (1UL << (shift - 1UL))) ||
> +		(grs == (1UL << (shift - 1UL)) && last != 0) || (exp > 15);
> +	return roundup ? __clc_rti(x) : __clc_rtz(x);
> +}
> #endif
> 
> #define __XFUNC(SUFFIX, VEC_SIZE, OFFSET, TYPE, STYPE, AS) \
> 	__FUNC(SUFFIX, VEC_SIZE, OFFSET, TYPE, STYPE, AS, __clc_noop) \
> 	__FUNC(SUFFIX ## _rtz, VEC_SIZE, OFFSET, TYPE, STYPE, AS, __clc_rtz) \
> 	__FUNC(SUFFIX ## _rtn, VEC_SIZE, OFFSET, TYPE, STYPE, AS, __clc_rtn) \
> -	__FUNC(SUFFIX ## _rtp, VEC_SIZE, OFFSET, TYPE, STYPE, AS, __clc_rtp)
> +	__FUNC(SUFFIX ## _rtp, VEC_SIZE, OFFSET, TYPE, STYPE, AS, __clc_rtp) \
> +	__FUNC(SUFFIX ## _rte, VEC_SIZE, OFFSET, TYPE, STYPE, AS, __clc_rte)
> 
> #define FUNC(SUFFIX, VEC_SIZE, OFFSET, TYPE, STYPE, AS) \
> 	__XFUNC(SUFFIX, VEC_SIZE, OFFSET, TYPE, STYPE, AS)
> -- 
> 2.14.3
> 
> _______________________________________________
> Libclc-dev mailing list
> Libclc-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/libclc-dev