FMAXP (vector)

Floating-point Maximum Pairwise (vector). This instruction creates a vector by concatenating the vector elements of the first source SIMD&FP register after the vector elements of the second source SIMD&FP register, reads each pair of adjacent vector elements from the concatenated vector, writes the larger of each pair of values into a vector, and writes the vector to the destination SIMD&FP register. All the values in this instruction are floating-point values.

When FPCR.AH is 0, the behavior is as follows for each pairwise operation:

• Negative zero compares less than positive zero.
• When FPCR.DN is 0, if either element is a NaN, the result is a quiet NaN.
• When FPCR.DN is 1, if either element is a NaN, the result is Default NaN.

When FPCR.AH is 1, the behavior is as follows for each pairwise operation:

• If both elements are zeros, regardless of the sign of either zero, the result is the second element.
• If either element is a NaN, regardless of the value of FPCR.DN, the result is the second element.

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 2 classes: Half-precision and Single-precision and double-precision

Half-precision
(FEAT_FP16)

if !IsFeatureImplemented(FEAT_FP16) then UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); constant integer esize = 16; constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize; boolean pair = (U == '1'); boolean minimum = (o1 == '1');

Single-precision and double-precision

integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); if sz:Q == '10' then UNDEFINED; constant integer esize = 32 << UInt(sz); constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize; boolean pair = (U == '1'); boolean minimum = (o1 == '1');