IA-32 Assembly Language Reference Manual

# Transcendental Instructions

## Partial Tangent (fptan)

```fptan
```

##### Example

Replace stack element 0 with its tangent and push a value of 1 onto the FPU stack.

`fptan`

## Partial Arctangent (fpatan)

```fpatan
```

##### Example

Divide stack element 1 by stack element 0, compute the arctangent and return the result in radians to stack element 1, then pop the stack.

`fpatan`

## 2x - 1 (f2xm1)

```f2xm1
```

##### Example

Replace the contents of stack element 0 (st) with the value of (2st-1).

`f2xm1`

## Y * log2 X (fyl2x)

```fyl2x
```

##### Example

Compute the logarithm (base-2) of stack element 0 and multiply the result by stack element 1 and return the result to stack element 1, then pop the stack.

`fy12x`

## Y * log 2 (X+1) (fyl2xp1)

```fyl2xp1
```

##### Example

Compute the logarithm (base-2) of stack element 0 plus 1.0 and multiply the result by stack element 1 and return the result to stack element 1, then pop the stack.

`fy12xpl`