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Floating-point Javascript Convert to Signed fixed-point, rounding toward Zero. This instruction converts the double-precision floating-point value in the SIMD&FP source register to a 32-bit signed integer using the Round towards Zero rounding mode, and writes the result to the general-purpose destination register. If the result is too large to be accommodated as a signed 32-bit integer, then the result is the integer modulo 232, as held in a 32-bit signed integer.

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.

Double-precision to 32-bit


Double-precision to 32-bit

FJCVTZS <Wd>, <Dn>

integer d = UInt(Rd);
integer n = UInt(Rn);

if !HaveFJCVTZSExt() then UNDEFINED;

Assembler Symbols


Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field.


Is the 64-bit name of the SIMD&FP source register, encoded in the "Rn" field.



bits(64) fltval;
bits(32) intval;

fltval = V[n];
intval = FPToFixedJS(fltval, FPCR, TRUE);
X[d] = ZeroExtend(intval<31:0>, 64);