fldl2e
Load Constant log2(e)
Pushes log2(e) onto the FPU register stack.
Pseudocode Operation
FPU_TOP ← FPU_TOP - 1;
if (FPU_TOP overflow) {
raise FPU_EXCEPTION;
}
ST(0) ← log₂(e);Encoding
Operands
Related
More in x87 FPU
Reference
Instruction Forms
| Opcode | Instruction | Op/En | 64/32-bit Mode | CPUID | Description |
|---|---|---|---|---|---|
| D9 E8 | FLD1 | Valid Valid | Push +1.0 onto the FPU register stack. | ||
| D9 E9 | FLDL2T | Valid Valid | Push log210 onto the FPU register stack. | ||
| D9 EA | FLDL2E | Valid Valid | Push log2e onto the FPU register stack. | ||
| D9 EB | FLDPI | Valid Valid | Push π onto the FPU register stack. | ||
| D9 EC | FLDLG2 | Valid Valid | Push log102 onto the FPU register stack. | ||
| D9 ED | FLDLN2 | Valid Valid | Push loge2 onto the FPU register stack. | ||
| D9 EE | FLDZ | Valid Valid | Push +0.0 onto the FPU register stack. |
Description
Push one of seven commonly used constants (in double extended-precision floating-point format) onto the FPU register stack. The constants that can be loaded with these instructions include +1.0, +0.0, log210, log2e, π, log102, and loge2. For each constant, an internal 66-bit constant is rounded (as specified by the RC field in the FPU control word) to double extended-precision floating-point format. The inexact-result exception (#P) is not generated as a result of the rounding, nor is the C1 flag set in the x87 FPU status word if the value is rounded up. See the section titled “Approximation of Pi” in Chapter 8 of the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1, for a description of the π constant. This instruction’s operation is the same in non-64-bit modes and 64-bit mode.
IA-32 Architecture Compatibility When the RC field is set to round-to-nearest, the FPU produces the same constants that is produced by the Intel 8087 and Intel 287 math coprocessors.
Operation
TOP := TOP - 1; ST(0) := CONSTANT;