guMtxCatL
# guMtxCatL [Function]

### Function

guMtxCatL

*Multiplies matrices (fixed point)*

### Syntax

```
#include <ultra64.h> /* gu.h */
void guMtxCatL(Mtx *m, Mtx *n, Mtx *res);
```

### Arguments

**m**
- Pointer to first matrix
**n**
- Pointer to second pointer
**res**
- Pointer to matrix resulting from the computation (
**m** x **n**)

### Returned value

None.

### Description

Executes a multiplication of the two matrices (**m**, **n**) and returns the result to the structure indicated by **res**. This function provides a useful way to process matrices on the host CPU. Floating point can be handled with the guMtxCatF function.

For details, see 1-5-2 "Matrix Multiplication" in Step 3 of the Kantan Manual. For an explanation of the fixed-point format, see gSPMatrix.

### Comment

It is alright for the resulting matrix **res** to comprise just one of the input matrices **m** or **n**.

The Mtx structure looks like this:

```
typedef long Mtx_t[4][4];
typedef union {
Mtx_t m;
long long int force_structure_alignment;
} Mtx;
```

### See also

gSPMatrix, guMtxCatF

### Revision history

03/01/99 Completely rewritten.