Floating-point Negated fused Multiply-Subtract (scalar). This instruction multiplies the values of the first two SIMD&FP source registers, subtracts the value of the third SIMD&FP source register, and writes the result to the destination SIMD&FP register.
A floating-point exception can be generated by this instruction. Depending on the settings in FPCR, the exception results in either a flag being set in FPSR, or a synchronous exception being generated. For more information, see Floating-point exception traps.
Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.
| 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 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | ftype | 1 | Rm | 1 | Ra | Rn | Rd | |||||||||||||||||
| o1 | o0 | ||||||||||||||||||||||||||||||
integer d = UInt(Rd); integer a = UInt(Ra); integer n = UInt(Rn); integer m = UInt(Rm); integer esize; case ftype of when '00' esize = 32; when '01' esize = 64; when '10' UNDEFINED; when '11' if HaveFP16Ext() then esize = 16; else UNDEFINED; boolean opa_neg = (o1 == '1'); boolean op1_neg = (o0 != o1);
| <Dd> |
Is the 64-bit name of the SIMD&FP destination register, encoded in the "Rd" field. |
| <Dn> |
Is the 64-bit name of the first SIMD&FP source register holding the multiplicand, encoded in the "Rn" field. |
| <Dm> |
Is the 64-bit name of the second SIMD&FP source register holding the multiplier, encoded in the "Rm" field. |
| <Da> |
Is the 64-bit name of the third SIMD&FP source register holding the minuend, encoded in the "Ra" field. |
| <Hd> |
Is the 16-bit name of the SIMD&FP destination register, encoded in the "Rd" field. |
| <Hn> |
Is the 16-bit name of the first SIMD&FP source register holding the multiplicand, encoded in the "Rn" field. |
| <Hm> |
Is the 16-bit name of the second SIMD&FP source register holding the multiplier, encoded in the "Rm" field. |
| <Ha> |
Is the 16-bit name of the third SIMD&FP source register holding the minuend, encoded in the "Ra" field. |
| <Sd> |
Is the 32-bit name of the SIMD&FP destination register, encoded in the "Rd" field. |
| <Sn> |
Is the 32-bit name of the first SIMD&FP source register holding the multiplicand, encoded in the "Rn" field. |
| <Sm> |
Is the 32-bit name of the second SIMD&FP source register holding the multiplier, encoded in the "Rm" field. |
| <Sa> |
Is the 32-bit name of the third SIMD&FP source register holding the minuend, encoded in the "Ra" field. |
CheckFPEnabled64(); bits(esize) operanda = V[a]; bits(esize) operand1 = V[n]; bits(esize) operand2 = V[m]; FPCRType fpcr = FPCR[]; boolean merge = IsMerging(fpcr); bits(128) result = if merge then V[a] else Zeros(); if opa_neg then operanda = FPNeg(operanda); if op1_neg then operand1 = FPNeg(operand1); Elem[result, 0, esize] = FPMulAdd(operanda, operand1, operand2, fpcr); V[d] = result;
Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41
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