sync_up: Formatting fixes

[libreriscv.git] / zfpacc_proposal.mdwn

diff --git a/zfpacc_proposal.mdwn b/zfpacc_proposal.mdwn
index eac608fccb5e192485481254ca8c9e06cb403b26..8b22582a5d984dacb72bb766a487a30045959e86 100644 (file)
--- a/zfpacc_proposal.mdwn
+++ b/zfpacc_proposal.mdwn
@@ -1,3 +1,4 @@
+
 # FP Accuracy proposal
 
 Credits:
@@ -20,6 +21,20 @@ this proposal.  Only ULP (Unit in Last Place) of the instruction *result*
 is permitted to meet alternative accuracy requirements, whilst still
 retaining the instruction's requested format.
 
+This proposal is *only* suitable for adding pre-existing accuracy standards
+where it is clearly established, well in advance of applications being
+written that conform to that standard, that dealing with variations in
+accuracy across hardware implementations is the responsibility of the
+application writer.  This is the case for both Vulkan and OpenCL.
+
+This proposal is *not* suitable for inclusion of "de-facto" (proprietary)
+accuracy standards (historic IBM Mainframe vs Ahmdahl incompatibility)
+where there was no prior agreement or notification to applications
+writers that variations in accuracy across hardware implementations
+would occur.  In the unlikely event that they *are* ever to be included
+(n the future, rather than as a Custom Extension, then, unlike Vulkan
+and OpenCL, they must **only** be added as "bit-for-bit compatible".
+
 # Extension of FCSR
 
 Zfpacc would use some of the the reserved bits of FCSR.  It would be treated
@@ -153,16 +168,18 @@ Comments:
 
 ### function accuracy in standards (opencl, vulkan)
 
+[[resources]] for OpenCL and Vulkan
+
 Vulkan requires full ieee754 precision for all F/D instructions except for fdiv and fsqrt.
 
-https://www.khronos.org/registry/vulkan/specs/1.0/html/vkspec.html#spirvenv-precision-operation
+<https://www.khronos.org/registry/vulkan/specs/1.1-extensions/html/chap40.html#spirvenv-precision-operation>
 
 Source is here:
 <https://github.com/KhronosGroup/Vulkan-Docs/blob/master/appendices/spirvenv.txt#L1172>
 
 OpenCL slightly different, suggest adding as an extra entry.
 
-https://www.khronos.org/registry/OpenCL/specs/2.2/html/OpenCL_Env.html#relative-error-as-ulps
+<https://www.khronos.org/registry/OpenCL/specs/2.2/html/OpenCL_Env.html#relative-error-as-ulps>
 
 Link, finds version 2.1 of opencl environment specification, table 8.4.1 however needs checking if it is the same as the above, which has "SPIRV" in it and is 2.2 not 2.1