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FSCALE
Scales the floating-point value in the destination operand by a power of 2. The scale factor is determined by the value of the source operand, which is treated as a signed integer. The destination value is multiplied by $2^{source}$.
The following table covers the supported source and destinations.
| source | destination(s) |
|---|---|
| reg | ST(0) |
| mN | ST(0) |
DO NOT support LOCK
The instruction operates on the FPU register stack; therefore, it is available in both 64-bit mode and compatibility mode. The source operand must be a valid memory location or register containing an i32.
The scale factor is extracted from the source operand as a signed integer. If the source operand is a memory location, it SHALL be accessed according to the specified size. Values of the scale factor that are too large to be represented in the floating-point exponent SHALL result in #O or #U. If the result is not exact, the #P exception is raised. The destination operand is always the top of the FPU stack, ST(0).