# ISA Comparison Table
-| ISA <br>name | Num <br>opcodes | Taxonomy / <br> Class | Predicate <br> Masks | Twin <br> Predication | Explicit <br> Vector regs | 128-bit | Bigint <br> capability | LDST <br> Fault-First | Data-dependent <br> Fail-first | Predicate-<br> Result |
-|--------------|-------------------|-----------------------|------------------------|-------------------------|------------------------------|---------|--------------------------|-------------------------|----------------------------------|-------------------------|
-| SVP64 | 5 {1} | Scalable {2} | yes | yes {3} | no {4} | n/a {5} | yes {6} | yes {7} | yes {8} | yes {9} |
-| VSX | 700+ | Packed SIMD | no | no | yes {10} | yes | no | no | no | no |
-| NEON | ~250 {11} | Predicated SIMD | yes | no | yes | yes | no | no | no | no |
-| SVE2 | ~1000 {12} | Scalable HW {13} | yes | no | yes | yes | no | yes {7} | no | no |
-| AVX-512 {14} | ~1000s {15} | Predicated SIMD | yes | no | yes | yes | no | no | no | no |
-| RVV {16} | ~190 | Scalable {17} | yes | no | yes | yes {18}| no | yes | no | no |
+| ISA <br>name | Num <br>opcodes | Taxonomy / <br> Class | Predicate <br> Masks | Twin <br> Predication | Explicit <br> Vector regs | 128-bit | Bigint <br> capability | LDST <br> Fault-First | Data-dependent <br> Fail-first | Predicate-<br> Result |
+|----------------|-------------------|-----------------------|------------------------|-------------------------|------------------------------|---------|--------------------------|-------------------------|----------------------------------|-------------------------|
+| SVP64 | 5 {1} | Scalable {2} | yes | yes {3} | no {4} | see {5} | yes {6} | yes {7} | yes {8} | yes {9} |
+| VSX | 700+ | Packed SIMD | no | no | yes {10} | yes | no | no | no | no |
+| NEON | ~250 {11} | Predicated SIMD | yes | no | yes | yes | no | no | no | no |
+| SVE2 | ~1000 {12} | Scalable HW {13} | yes | no | yes | yes | no | yes {7} | no | no |
+| AVX-512 {14} | ~1000s {15} | Predicated SIMD | yes | no | yes | yes | no | no | no | no |
+| RVV {16} | ~190 | Scalable {17} | yes | no | yes | yes {18}| no | yes | no | no |
+| Aurora SX {19} | ~250 | Scalable {20} | yes | no | yes | no | no | no | no | no |
* {1}: plus EXT001 24-bit prefixing. See [[sv/svp64]]
* {2}: A 2-Dimensional Scalable Vector ISA with both Horizontal-First and Vertical-First Modes. See [[sv/vector_isa_comparison]]
* {7} See [[sv/svp64/appendix]] and [ARM SVE Fault-First](https://alastairreid.github.io/papers/sve-ieee-micro-2017.pdf)
* {8} Based on LD/ST Fail-first, extended to data. See [[sv/svp64/appendix]]
* {9} Turns standard ops into a type of "cmp". See [[sv/svp64/appendix]]
-* {10} VSX's Vector Registers are mis-named: they are PackedSIMD.
+* {10} VSX's Vector Registers are mis-named: they are 100% PackedSIMD. AVX-512 is not a Vector ISA either. See [Flynn's Taxonomy](https://en.wikipedia.org/wiki/Flynn%27s_taxonomy)
* {11} difficult to ascertain, see [NEON/VFP](https://developer.arm.com/documentation/den0018/a/NEON-and-VFP-Instruction-Summary/List-of-all-NEON-and-VFP-instructions).
Critically depends on ARM Scalar instructions
* {12} difficult to exactly ascertain, see ARM Architecture Reference Manual Supplement, DDI 0584. Critically depends on ARM Scalar instructions.
* {16}: [RVV Spec](https://github.com/riscv/riscv-v-spec/blob/master/v-spec.adoc)
* {17}: Like the original Cray RVV is a truly scalable Vector ISA (Cray setvl instruction).
* {18}: like SVP64 it is up to the hardware implementor to choose whether to support 128-bit elements.
+* {19}: [NEC SX Aurora](https://ftp.libre-soc.org/NEC_SX_Aurora_TSUBASA_VectorEngine-as-manual-v1.2.pdf) is based on the original Cray Vectors
+* {20}: Like the original Cray Vectors the ISA is independent of the underlying hardware.
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