Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

## FCMGT (zero)

Floating-point Compare Greater than zero (vector). This instruction reads each floating-point value in the source SIMD&FP register and if the value is greater than zero sets every bit of the corresponding vector element in the destination SIMD&FP register to one, otherwise sets every bit of the corresponding vector element in the destination SIMD&FP register to zero.

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 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.

It has encodings from 4 classes: Scalar half precision , Scalar single-precision and double-precision , Vector half precision and Vector single-precision and double-precision

### Scalar half precision
(FEAT_FP16)

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 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | Rn | Rd
| U |  |  |  |  | op |  |  |

####

FCMGT <Hd>, <Hn>, #0.0

if !HaveFP16Ext() then UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); integer esize = 16; integer datasize = esize; integer elements = 1; CompareOp comparison; case op:U of when '00' comparison = CompareOp_GT; when '01' comparison = CompareOp_GE; when '10' comparison = CompareOp_EQ; when '11' comparison = CompareOp_LE;

### Scalar single-precision and double-precision

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 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | sz | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | Rn | Rd
| U |  |  |  |  |  | op |  |  |

####

FCMGT <V><d>, <V><n>, #0.0

integer d = UInt(Rd); integer n = UInt(Rn); integer esize = 32 << UInt(sz); integer datasize = esize; integer elements = 1; CompareOp comparison; case op:U of when '00' comparison = CompareOp_GT; when '01' comparison = CompareOp_GE; when '10' comparison = CompareOp_EQ; when '11' comparison = CompareOp_LE;

### Vector half precision
(FEAT_FP16)

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 | Q | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | Rn | Rd
|  | U |  |  |  |  | op |  |  |

####

FCMGT <Vd>.<T>, <Vn>.<T>, #0.0

if !HaveFP16Ext() then UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); integer esize = 16; integer datasize = if Q == '1' then 128 else 64; integer elements = datasize DIV esize; CompareOp comparison; case op:U of when '00' comparison = CompareOp_GT; when '01' comparison = CompareOp_GE; when '10' comparison = CompareOp_EQ; when '11' comparison = CompareOp_LE;

### Vector single-precision and double-precision

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 | Q | 0 | 0 | 1 | 1 | 1 | 0 | 1 | sz | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | Rn | Rd
|  | U |  |  |  |  |  | op |  |  |

####

FCMGT <Vd>.<T>, <Vn>.<T>, #0.0

integer d = UInt(Rd); integer n = UInt(Rn); if sz:Q == '10' then UNDEFINED; integer esize = 32 << UInt(sz); integer datasize = if Q == '1' then 128 else 64; integer elements = datasize DIV esize; CompareOp comparison; case op:U of when '00' comparison = CompareOp_GT; when '01' comparison = CompareOp_GE; when '10' comparison = CompareOp_EQ; when '11' comparison = CompareOp_LE;

### Assembler Symbols

<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.

<V> | Is a width specifier, encoded in sz:
sz | <V>
--- | ---
0 | S
1 | D

<d> | Is the number of the SIMD&FP destination register, encoded in the "Rd" field.

<n> | Is the number of the SIMD&FP source register, encoded in the "Rn" field.

<Vd> | Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<T> | For the half-precision variant: is an arrangement specifier, encoded in Q:
Q | <T>
--- | ---
0 | 4H
1 | 8H
| For the single-precision and double-precision variant: is an arrangement specifier, encoded in sz:Q:
sz | Q | <T>
--- | --- | ---
0 | 0 | 2S
0 | 1 | 4S
1 | 0 | RESERVED
1 | 1 | 2D

<Vn> | Is the name of the SIMD&FP source register, encoded in the "Rn" field.

### Operation

CheckFPAdvSIMDEnabled64(); bits(datasize) operand = V[n, datasize]; bits(datasize) result; bits(esize) zero = FPZero('0', esize); bits(esize) element; boolean test_passed; for e = 0 to elements-1 element = Elem[operand, e, esize]; case comparison of when CompareOp_GT test_passed = FPCompareGT(element, zero, FPCR[]); when CompareOp_GE test_passed = FPCompareGE(element, zero, FPCR[]); when CompareOp_EQ test_passed = FPCompareEQ(element, zero, FPCR[]); when CompareOp_LE test_passed = FPCompareGE(zero, element, FPCR[]); when CompareOp_LT test_passed = FPCompareGT(zero, element, FPCR[]); Elem[result, e, esize] = if test_passed then Ones(esize) else Zeros(esize); V[d, datasize] = result;

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

Internal version only: isa v33.64, AdvSIMD v29.12, pseudocode v2023-06_rel, sve v2023-06_rel ; Build timestamp: 2023-07-04T19:42

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