x86mftop
LBT intrinsic · group: x86 FPU
Synopsis
Instruction: x86mftop rd
CPU Flags: LBT
Description
Move from x87 FPU stack top pointer: read the current x87 TOP (stack top index, 3-bit) into rd.
Latency and Throughput
| CPU | µarch | Latency | Throughput (IPC) |
|---|---|---|---|
| 3C5000 | LA464 | N/A | 4 |
| 3C6000 | LA664 | N/A | 4 |