frinti

Floating-Point Round to Integral (Current)

FRINTI <Hd|Sd|Dd>, <Hn|Sn|Dn>

Rounds float to integral value using current FPCR rounding mode.

Details

Rounds a floating-point scalar value to an integral value using the current rounding mode specified in the FPCR (Floating-Point Control Register). The rounding behavior depends on the RMode field in FPCR. This is an AArch64-only instruction that does not modify condition flags.

Pseudocode Operation

rounded_val ← RoundToIntegral_CurrentMode(Vn)   
Vd ← rounded_val

Example

FRINTI Dd, Dn

Encoding

Binary Layout
0
0
0
11110
00
1001
111
10000
Rn
Rd
 
Format FP Data Processing
Opcode 0x1E27C000
Extension Floating Point

Operands

  • Vd
    Destination SIMD/FP vector register
  • Vn
    First source SIMD/FP vector register

Reference (Arm A64 ISA)

Instruction Forms

Encoding Instruction ISA Bit pattern
0x6507A000 FRINTI <Zd>.<T>, <Pg>/M, <Zn>.<T> A64 01100101 | size | 000 | 11 | 1 | 101 | Pg | Zn | Zd
0x2EF99800 FRINTI <Vd>.<T>, <Vn>.<T> A64 0 | Q | 1 | 01110 | 1 | 1111001100 | 1 | 10 | Rn | Rd
0x2EA19800 FRINTI <Vd>.<T>, <Vn>.<T> A64 0 | Q | 1 | 01110 | 1 | sz | 100001100 | 1 | 10 | Rn | Rd
0x1EE7C000 FRINTI <Hd>, <Hn> A64 0 | 0 | 0 | 11110 | 11 | 1001 | 111 | 10000 | Rn | Rd
0x1E27C000 FRINTI <Sd>, <Sn> A64 0 | 0 | 0 | 11110 | 00 | 1001 | 111 | 10000 | Rn | Rd
0x1E67C000 FRINTI <Dd>, <Dn> A64 0 | 0 | 0 | 11110 | 01 | 1001 | 111 | 10000 | Rn | Rd

Description

Floating-point Round to Integral, using current rounding mode (scalar). This instruction rounds a floating-point value in the SIMD&FP source register to an integral floating-point value of the same size using the rounding mode that is determined by the FPCR, and writes the result to the SIMD&FP destination register. A zero input gives a zero result with the same sign, an infinite input gives an infinite result with the same sign, and a NaN is propagated as for normal arithmetic. 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.

Operation

CheckFPEnabled64();

boolean merge = IsMerging(FPCR);
bits(128) result = if merge then V[d, 128] else Zeros(128);
bits(esize) operand = V[n, esize];

Elem[result, 0, esize] = FPRoundInt(operand, FPCR, rounding, FALSE);

V[d, 128] = result;