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FABS (scalar)

Floating-point Absolute value (scalar). This instruction calculates the absolute value in the SIMD&FP source register and writes the result to the SIMD&FP destination register.

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.

313029282726252423222120191817161514131211109876543210
00011110ftype100000110000RnRd
opc

Half-precision (ftype == 11)
(Armv8.2)

FABS <Hd>, <Hn>

Single-precision (ftype == 00)

FABS <Sd>, <Sn>

Double-precision (ftype == 01)

FABS <Dd>, <Dn>

integer d = UInt(Rd); integer n = UInt(Rn); integer esize; integer datasize; case ftype of when '00' esize = 32; when '01' esize = 64; when '00' datasize = 32; when '01' datasize = 64; when '10' UNDEFINED; when '11' if HaveFP16Ext() then esize = 16; datasize = 16; else UNDEFINED; FPUnaryOp fpop; case opc of when '00' fpop = FPUnaryOp_MOV; when '01' fpop = FPUnaryOp_ABS; when '10' fpop = FPUnaryOp_NEG; when '11' fpop = FPUnaryOp_SQRT;

Assembler Symbols

<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 SIMD&FP source register, encoded in the "Rn" 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 SIMD&FP source register, encoded in the "Rn" 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 SIMD&FP source register, encoded in the "Rn" field.

Operation

CheckFPAdvSIMDEnabled64();(); bits(datasize) result; bits(datasize) operand = FPCRType fpcr = FPCR[]; boolean merge = fpop != FPUnaryOp_MOV && IsMerging(fpcr); bits(128) result = if merge then V[d] else[n]; case fpop of when Zeros(); bits(esize) operand = V[n]; case fpop of when FPUnaryOp_MOV result = operand; whenElem[result, 0, esize] = operand; when FPUnaryOp_ABS result =Elem[result, 0, esize] = FPAbs(operand); when FPUnaryOp_NEG result =Elem[result, 0, esize] = FPNeg(operand); when FPUnaryOp_SQRT Elem[result, 0, esize] =result = FPSqrt(operand, fpcr);(operand, FPCR); V[d] = result;


Internal version only: isa v32.12v32.06, AdvSIMD v29.04, pseudocode v2020-09_xmlv2020-06_rel, sve v2020-09_rc2bv2020-06_rel0 ; Build timestamp: 2020-09-30T192020-07-03T13:1613

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