[llvm] [llvm][AArch64][Assembly]: Add FP8 instructions assembly and disassembly. (PR #69632)

[via llvm-commits]

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@@ -6056,6 +6056,53 @@ multiclass SIMDThreeSameVectorFML<bit U, bit b13, bits<3> size, string asm,
 }
 
 
+// FP8 assembly/disassembly classes
+
+//----------------------------------------------------------------------------
+// FP8 Advanced SIMD three-register extension
+//----------------------------------------------------------------------------
+class BaseSIMDThreeVectors<bit Q, bit U, bits<2> size, bits<4> op,
+                           RegisterOperand regtype1,
+                           RegisterOperand regtype2, string asm,
+                           string kind1, string kind2>
+  : I<(outs regtype1:$Rd), (ins regtype2:$Rn, regtype2:$Rm), asm,
+      "\t$Rd" # kind1 # ", $Rn" # kind2 # ", $Rm" # kind2, "", []>, Sched<[]> {
+  bits<5> Rd;
+  bits<5> Rn;
+  bits<5> Rm;
+  let Inst{31}    = 0;
+  let Inst{30}    = Q;
+  let Inst{29}    = U;
+  let Inst{28-24} = 0b01110;
+  let Inst{23-22} = size;
+  let Inst{21}    = 0b0;
+  let Inst{20-16} = Rm;
+  let Inst{15}    = 0b1;
+  let Inst{14-11} = op;
+  let Inst{10}    = 0b1;
+  let Inst{9-5}   = Rn;
+  let Inst{4-0}   = Rd;
+}
+
+
+// FCVTN (FP16 to FP8)
+multiclass SIMDThreeSameSizeVectorCvt<string asm> {
+   def v8f8 : BaseSIMDThreeVectors<0b0, 0b0, 0b01, 0b1110, V64, V64, asm, ".8b",".4h">;
+   def v16f8 : BaseSIMDThreeVectors<0b1, 0b0, 0b01, 0b1110,  V128, V128, asm, ".16b", ".8h">;
+}
+
+class BaseSIMDThreeSameSizeVectorFP8Tied<bit Q, bits<2> sz, string asm, string kind1,
+                                 string kind2, RegisterOperand RegType> :
+        BaseSIMDThreeSameVectorTied<Q, 0b0, {sz,0b0}, 0b11110, RegType, asm, kind1, []> {
+  let AsmString = !strconcat(asm, "{\t$Rd" # kind1 # ", $Rn" # kind2 # ", $Rm" # kind2 # "}");
+}
+
+// FCVTN, FCVTN2 (FP32 to FP8)
+multiclass SIMDThreeVectorCvt<string asm> {
+   def v8f8 : BaseSIMDThreeVectors<0b0, 0b0, 0b00, 0b1110, V64, V128, asm, ".8b", ".4s">;
+   def 2v16f8 : BaseSIMDThreeSameSizeVectorFP8Tied<0b1, 0b00, asm#2, ".16b", ".4s", V128>;
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CarolineConcatto wrote:

You should be able to use BaseSIMDThreeSameVectorDot instead of BaseSIMDThreeSameSizeVectorFP8Tied

https://github.com/llvm/llvm-project/pull/69632