Omit the reciprocal [sqrt] approximation operations.

To be debated in #3.

Add a complete list of omitted operations to Overview.md.

proposals/simd/Overview.md

@@ -15,16 +15,19 @@ There are three parts to the proposal:
 3. This document which describes the mapping between WebAssembly and the
    portable specification.
 
-Referencing a common specification of the portable SIMD semantics reduces the
-work required to support both SIMD.js and WebAssembly SIMD in the same
-implementation.
-
 # Mapping portable SIMD to WebAssembly
 
 The types and operations in the portable SIMD specification are relatively
 straightforward to map to WebAssembly. This section describes the details of
 the mapping.
 
+The following operations are *not* provided in WebAssembly:
+
+- `f*.maxNum` and `f*.minNum`. These NaN-suppressing operations don't exist in
+  scalar WebAssembly versions either. The NaN-propagating versions are provided.
+- `f*.reciprocalApproximation` and `f*.reciprocalSqrtApproximation` are omitted
+  from WebAssembly pending further discussion.
+
 ## New value types
 
 The following value types are added to the WebAssembly type system to support

proposals/simd/webassembly-opcodes.md

@@ -156,8 +156,6 @@ and output vectors:
 | `f32x4.max(a: v128, b: v128) -> v128` | [f32x4.max](portable-simd.md#nan-propagating-maximum) |
 | `f32x4.div(a: v128, b: v128) -> v128` | [f32x4.div](portable-simd.md#division) |
 | `f32x4.sqrt(a: v128) -> v128` | [f32x4.sqrt](portable-simd.md#square-root) |
-| `f32x4.reciprocalApproximation(a: v128) -> v128` | [f32x4.reciprocalApproximation](portable-simd.md#reciprocal-approximation) |
-| `f32x4.reciprocalSqrtApproximation(a: v128) -> v128` | [f32x4.reciprocalSqrtApproximation](portable-simd.md#reciprocal-square-root-approximation) |
 | `f32x4.convert_s/i32x4(a: v128) -> v128` | [f32x4.fromSignedInt](portable-simd.md#integer-to-floating-point) |
 | `f32x4.convert_u/i32x4(a: v128) -> v128` | [f32x4.fromUnsignedInt](portable-simd.md#integer-to-floating-point) |
 
@@ -217,8 +215,6 @@ and output vectors:
 | `f64x2.max(a: v128, b: v128) -> v128` | [f64x2.max](portable-simd.md#nan-propagating-maximum) |
 | `f64x2.div(a: v128, b: v128) -> v128` | [f64x2.div](portable-simd.md#division) |
 | `f64x2.sqrt(a: v128) -> v128` | [f64x2.sqrt](portable-simd.md#square-root) |
-| `f64x2.reciprocalApproximation(a: v128) -> v128` | [f64x2.reciprocalApproximation](portable-simd.md#reciprocal-approximation) |
-| `f64x2.reciprocalSqrtApproximation(a: v128) -> v128` | [f64x2.reciprocalSqrtApproximation](portable-simd.md#reciprocal-square-root-approximation) |
 | `f64x2.convert_s/i64x2(a: v128) -> v128` | [f64x2.fromSignedInt](portable-simd.md#integer-to-floating-point) |
 | `f64x2.convert_u/i64x2(a: v128) -> v128` | [f64x2.fromUnsignedInt](portable-simd.md#integer-to-floating-point) |