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+# 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