This content has not been validated; it was AI-generated following the x86-64 ISA Documentation generation process to maintain high quality. However, as no human has verified this data, errors may exist. If the accuracy of this data is critical, please consult the Intel SDM. The model used to generate this is gemma4:31b

FBLD

Loads a long real (80-bit extended precision) floating-point value from memory and pushes it onto the floating-point register stack.

The table below covers the supported source and destination.

DO NOT support LOCK

This instruction is available in 64-bit mode, but it specifically targets the x87 FPU stack. It is not available in compatibility mode if the x87 state is not preserved or enabled.

The operand MUST be a 10-byte extended precision floating-point value. Using an incorrect memory size or an unsupported address alignment may trigger a general protection fault (#GP).

The instruction increments the floating-point stack pointer (TOP). If the stack is full (TOP=0), a stack overflow exception (#SF) occurs.