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Diffstat (limited to 'AstSemantics.md')
| -rw-r--r-- | AstSemantics.md | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/AstSemantics.md b/AstSemantics.md index d01f004..6b91bd8 100644 --- a/AstSemantics.md +++ b/AstSemantics.md @@ -8,7 +8,7 @@ The operations available in the AST are defined here in language-independent way but closely match operations in many programming languages and are efficiently implementable on all modern computers. Floating point arithmetic follows the IEEE 754 standard and unless otherwise -specified uses the round-to-nearest mode. +specified uses the round-to-nearest ties-to-even mode. ## Addressing local variables @@ -257,7 +257,9 @@ Additional 32-bit integer Operations under consideration: * Int32UMin - unsigned minimum * Int32UMax - unsigned maximum -The behavior of division-by-zero and (INT32_MIN/-1) needs clarification. +The behavior of division-by-zero, remainder-by-zero, (INT32_MIN/-1), and shifts +by negative or at least 32 needs clarification. + An efficient polyfill to asm.js would suggest division-by-zero results in 0 although it's possible for the asm.js polyfill to simply be wrong in this corner case. Other options include throwing an exception or producing an @@ -305,17 +307,11 @@ All 32-bit floating point operations conform to the IEEE-754 standard. Operations under consideration: -Note that the IEEE 754 standard does not require extended operations -like transcendental functions to have a specified precision. -It does require them to define and use a consistent rounding quantum. - -The rounding behavior of the operations under consideration needs clarification. - ## Datatype conversions and truncations Datatype conversions are mostly used to convert floating point numbers to -integers and vice versa. The exact details for out-of-range values and rounding -need further clarification. +integers and vice versa. The exact details for out-of-range values need +further clarification. * Int32FromFloat64 - truncate a 64-bit float to a signed integer * Int32FromFloat32 - truncate a 32-bit float to a signed integer @@ -362,3 +358,8 @@ since this provides greater control over precision/performance tradeoffs. * Float32Ln - natural logarithm * Float32Pow - exponentiate +Note that the IEEE 754 standard does not require extended operations +like transcendental functions to have a specified precision. +It does require them to define and use a consistent rounding quantum. + +The rounding behavior of the operations under consideration needs clarification. |