Integer absolute value instructions (#128)

Author: Maratyszcza

proposals/simd/BinarySIMD.md

@@ -199,3 +199,6 @@ The `v8x16.shuffle` instruction has 16 bytes after `simdop`.
 | `v128.andnot`              |    `0xd8`| -                  |
 | `i8x16.avgr_u`             |    `0xd9`|                    |
 | `i16x8.avgr_u`             |    `0xda`|                    |
+| `i8x16.abs`                |    `0xe1`| -                  |
+| `i16x8.abs`                |    `0xe2`| -                  |
+| `i32x4.abs`                |    `0xe3`| -                  |

proposals/simd/ImplementationStatus.md

@@ -92,6 +92,7 @@
 | `i8x16.max_s`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
 | `i8x16.max_u`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
 | `i8x16.avgr_u`             |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
+| `i8x16.abs`                |                           |                       |                    |                    |
 | `i16x8.neg`                |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
 | `i16x8.any_true`           |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
 | `i16x8.all_true`           |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
@@ -110,6 +111,7 @@
 | `i16x8.max_s`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
 | `i16x8.max_u`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
 | `i16x8.avgr_u`             |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
+| `i16x8.abs`                |                           |                       |                    |                    |
 | `i32x4.neg`                |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
 | `i32x4.any_true`           |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
 | `i32x4.all_true`           |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
@@ -123,6 +125,7 @@
 | `i32x4.min_u`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
 | `i32x4.max_s`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
 | `i32x4.max_u`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: |                    |
+| `i32x4.abs`                |                           |                       |                    |                    |
 | `i64x2.neg`                |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
 | `i64x2.shl`                |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
 | `i64x2.shr_s`              |               `-msimd128` |    :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |

proposals/simd/SIMD.md

@@ -503,6 +503,18 @@ def S.avgr_u(a, b):
     return S.lanewise_binary(S.RoundingAverage, S.AsUnsigned(a), S.AsUnsigned(b))
 ```
 
+### Lane-wise integer absolute value
+* `i8x16.abs(a: v128) -> v128`
+* `i16x8.abs(a: v128) -> v128`
+* `i32x4.abs(a: v128) -> v128`
+
+Lane-wise wrapping absolute value.
+
+```python
+def S.abs(a):
+    return S.lanewise_unary(abs, S.AsSigned(a))
+```
+
 ## Bit shifts
 
 ### Left shift by scalar
@@ -791,7 +803,7 @@ def S.neg(a):
     return S.lanewise_unary(ieee.negate, a)
 ```
 
-### Absolute value
+### Floating-point absolute value
 * `f32x4.abs(a: v128) -> v128`
 * `f64x2.abs(a: v128) -> v128`