From 490d2d3f3ec55c0342ba9fc62e697b18db72b3ee Mon Sep 17 00:00:00 2001 From: Jacob Lifshay Date: Tue, 9 Oct 2018 21:27:30 -0700 Subject: [PATCH] add SimpleV Grouping Proposal.md --- docs/SimpleV Grouping Proposal.md | 95 +++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 docs/SimpleV Grouping Proposal.md diff --git a/docs/SimpleV Grouping Proposal.md b/docs/SimpleV Grouping Proposal.md new file mode 100644 index 0000000..c549e36 --- /dev/null +++ b/docs/SimpleV Grouping Proposal.md @@ -0,0 +1,95 @@ +# Proposal for Element-Grouping in SimpleV on RV64GC + +#### Notes + +i*N* is used to denote a sign-agnostic *N*-bit integer, +similarly f*N* is a *N*-bit floating-point number. *VL* is used to denote the current vector length. + +For the unused elements in an integer register, the used element closest to the MSB is sign-extended on write and the unused elements are ignored on read. +The unused elements in a floating-point register are treated as-if they are set to all ones on write and are ignored on read, matching the existing standard for storing smaller FP values in larger registers. + +For grouped modes, *VL* denotes the number of groups, not the number of elements. + +### Group Size 1 + +| Mode | # Regs | Regs/Group | Elms/Reg | Packed/Non-packed SIMD | +|------------|--------|------------|----------|--------------------------| +| i8x1x*VL* | 1x*VL* | 1 | 1 | i64x1x*VL* (Non-packed) | +| i16x1x*VL* | 1x*VL* | 1 | 1 | i64x1x*VL* (Non-packed) | +| i32x1x*VL* | 1x*VL* | 1 | 1 | i64x1x*VL* (Non-packed) | +| i64x1x*VL* | 1x*VL* | 1 | 1 | i64x1x*VL* (Non-packed) | +| f16x1x*VL* | 1x*VL* | 1 | 1 | f16x1x*VL* (Non-packed) | +| f32x1x*VL* | 1x*VL* | 1 | 1 | f32x1x*VL* (Non-packed) | +| f64x1x*VL* | 1x*VL* | 1 | 1 | f64x1x*VL* (Non-packed) | + +### Group Size 2 + +| Mode | # Regs | Regs/Group | Elms/Reg | Packed/Non-packed SIMD | +|------------|--------|------------|----------|--------------------------| +| i8x2x*VL* | 1x*VL* | 1 | 2 | Not supported | +| i16x2x*VL* | 1x*VL* | 1 | 2 | Not supported | +| i32x2x*VL* | 1x*VL* | 1 | 2 | i32x2x*VL* (Packed) | +| i64x2x*VL* | 2x*VL* | 2 | 1 | i64x2x*VL* (Non-packed)* | +| f16x2x*VL* | 1x*VL* | 1 | 2 | Not supported | +| f32x2x*VL* | 1x*VL* | 1 | 2 | f32x2x*VL* (Packed) | +| f64x2x*VL* | 2x*VL* | 2 | 1 | f64x2x*VL* (Non-packed)* | + +\* Not supported unless *VL* is changed + +### Group Size 3 + +| Mode | # Regs | Regs/Group | Elms/Reg | Packed/Non-packed SIMD | +|------------|--------|------------|----------|--------------------------| +| i8x3x*VL* | 1x*VL* | 1 | 3 | Not supported | +| i16x3x*VL* | 1x*VL* | 1 | 3 | Not supported | +| i32x3x*VL* | 2x*VL* | 2 | 2 | Not supported | +| i64x3x*VL* | 3x*VL* | 3 | 1 | i64x3x*VL* (Non-packed)* | +| f16x3x*VL* | 1x*VL* | 1 | 3 | Not supported | +| f32x3x*VL* | 2x*VL* | 2 | 2 | Not supported | +| f64x3x*VL* | 3x*VL* | 3 | 1 | f64x3x*VL* (Non-packed)* | + +\* Not supported unless *VL* is changed + +### Group Size 4 + +| Mode | # Regs | Regs/Group | Elms/Reg | Packed/Non-packed SIMD | +|------------|--------|------------|----------|--------------------------| +| i8x4x*VL* | 1x*VL* | 1 | 4 | Not supported | +| i16x4x*VL* | 1x*VL* | 1 | 4 | i16x4x*VL* (Packed) | +| i32x4x*VL* | 2x*VL* | 2 | 2 | i32x4x*VL* (Packed)* | +| i64x4x*VL* | 4x*VL* | 4 | 1 | i64x4x*VL* (Non-packed)* | +| f16x4x*VL* | 1x*VL* | 1 | 4 | f16x4x*VL* (Packed) | +| f32x4x*VL* | 2x*VL* | 2 | 2 | f32x4x*VL* (Packed)* | +| f64x4x*VL* | 4x*VL* | 4 | 1 | f64x4x*VL* (Non-packed)* | + +\* Not supported unless *VL* is changed + +... + +### Group Size 7 + +| Mode | # Regs | Regs/Group | Elms/Reg | Packed/Non-packed SIMD | +|------------|--------|------------|----------|--------------------------| +| i8x7x*VL* | 1x*VL* | 1 | 7 | Not supported | +| i16x7x*VL* | 2x*VL* | 2 | 4 | Not supported | +| i32x7x*VL* | 4x*VL* | 4 | 2 | Not supported | +| i64x7x*VL* | 7x*VL* | 7 | 1 | i64x7x*VL* (Non-packed)* | +| f16x7x*VL* | 2x*VL* | 2 | 4 | Not supported | +| f32x7x*VL* | 4x*VL* | 4 | 2 | Not supported | +| f64x7x*VL* | 7x*VL* | 7 | 1 | f64x7x*VL* (Non-packed)* | + +\* Not supported unless *VL* is changed + +### Group Size 8 + +| Mode | # Regs | Regs/Group | Elms/Reg | Packed/Non-packed SIMD | +|------------|--------|------------|----------|--------------------------| +| i8x8x*VL* | 1x*VL* | 1 | 8 | i8x8x*VL* (Packed) | +| i16x8x*VL* | 2x*VL* | 2 | 4 | i16x8x*VL* (Packed)* | +| i32x8x*VL* | 4x*VL* | 4 | 2 | i32x8x*VL* (Packed)* | +| i64x8x*VL* | 8x*VL* | 8 | 1 | i64x8x*VL* (Non-packed)* | +| f16x8x*VL* | 2x*VL* | 2 | 4 | f16x8x*VL* (Packed)* | +| f32x8x*VL* | 4x*VL* | 4 | 2 | f32x8x*VL* (Packed)* | +| f64x8x*VL* | 8x*VL* | 8 | 1 | f64x8x*VL* (Non-packed)* | + +\* Not supported unless *VL* is changed -- 2.30.2