BFloat16 floating-point multiply-subtract long from single-precision (top)
This BFloat16 floating-point multiply-subtract long instruction widens the odd-numbered BFloat16 elements in the first source vector and the corresponding elements in the second source vector to single-precision format and then destructively multiplies and subtracts these values without intermediate rounding from the single-precision elements of the destination vector that overlap with the corresponding BFloat16 elements in the source vectors. This instruction is unpredicated.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | Zm | 1 | 0 | 1 | 0 | 0 | 1 | Zn | Zda | ||||||||||||
| o2 | op | T | |||||||||||||||||||||||||||||
if !HaveSME2() && !HaveSVE2p1() then UNDEFINED; integer n = UInt(Zn); integer m = UInt(Zm); integer da = UInt(Zda); boolean op1_neg = TRUE;
| <Zda> |
Is the name of the third source and destination scalable vector register, encoded in the "Zda" field. |
| <Zn> |
Is the name of the first source scalable vector register, encoded in the "Zn" field. |
| <Zm> |
Is the name of the second source scalable vector register, encoded in the "Zm" field. |
CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV 32; bits(VL) operand1 = Z[n, VL]; bits(VL) operand2 = Z[m, VL]; bits(VL) operand3 = Z[da, VL]; bits(VL) result; for e = 0 to elements-1 bits(16) element1 = Elem[operand1, 2 * e + 1, 16]; bits(16) element2 = Elem[operand2, 2 * e + 1, 16]; bits(32) element3 = Elem[operand3, e, 32]; if op1_neg then element1 = BFNeg(element1); Elem[result, e, 32] = BFMulAddH(element3, element1, element2, FPCR); Z[da, VL] = result;
This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX instruction must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is unpredictable:
Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46
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