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.
This instruction can generate a floating-point exception. 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 exceptions and 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 | |||||||||||||||||
| M | S | o1 | o0 | ||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_FP) then EndOfDecode(Decode_UNDEF); if ftype == '10' || (ftype == '11' && !IsFeatureImplemented(FEAT_FP16)) then EndOfDecode(Decode_UNDEF); constant integer d = UInt(Rd); constant integer n = UInt(Rn); constant integer m = UInt(Rm); constant integer a = UInt(Ra); constant integer esize = 8 << UInt(ftype EOR '10');
| <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. |
| <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. |
CheckFPEnabled64(); constant bits(esize) addend = FPNeg(V[a, esize], FPCR); constant bits(esize) operand1 = V[n, esize]; constant bits(esize) operand2 = V[m, esize]; bits(128) result = if IsMerging(FPCR) then V[a, 128] else Zeros(128); Elem[result, 0, esize] = FPMulAdd(addend, operand1, operand2, FPCR); V[d, 128] = result;
Internal version only: aarchmrs v2024-12_rel, pseudocode v2024-12_rel ; Build timestamp: 2024-12-15T22:18
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