OSSetGQR[n]

Syntax

#include <revolution/os.h>

// GQR type formats
#define OS_GQR_F32 0x0000
#define OS_GQR_U8  0x0004
#define OS_GQR_U16 0x0005
#define OS_GQR_S8  0x0006
#define OS_GQR_S16 0x0007

// GQR scale factors
#define OS_GQR_SCALE_NONE   0
#define OS_GQR_SCALE_2      1
#define OS_GQR_SCALE_4      2
#define OS_GQR_SCALE_8      3
#define OS_GQR_SCALE_16     4
#define OS_GQR_SCALE_32     5
#define OS_GQR_SCALE_64     6
#define OS_GQR_SCALE_128    7
#define OS_GQR_SCALE_256    8
#define OS_GQR_SCALE_512    9
#define OS_GQR_SCALE_1024   10
#define OS_GQR_SCALE_2048   11
#define OS_GQR_SCALE_4096   12
#define OS_GQR_SCALE_8192   13
#define OS_GQR_SCALE_16384  14
#define OS_GQR_SCALE_32768  15
#define OS_GQR_SCALE_65536  16
#define OS_GQR_SCALE_MAX    31

#define OS_GQR_DIVIDE_2     63
#define OS_GQR_DIVIDE_4     62
#define OS_GQR_DIVIDE_8     61
#define OS_GQR_DIVIDE_16    60
#define OS_GQR_DIVIDE_32    59
#define OS_GQR_DIVIDE_64    58
#define OS_GQR_DIVIDE_128   57
#define OS_GQR_DIVIDE_256   56
#define OS_GQR_DIVIDE_512   55
#define OS_GQR_DIVIDE_1024  54
#define OS_GQR_DIVIDE_2048  53
#define OS_GQR_DIVIDE_4096  52
#define OS_GQR_DIVIDE_8192  51
#define OS_GQR_DIVIDE_16384 50
#define OS_GQR_DIVIDE_32768 49
#define OS_GQR_DIVIDE_65536 48
#define OS_GQR_DIVIDE_MAX   32

inline void OSSetGQR2(u32 type, u32 scale);
inline void OSSetGQR3(u32 type, u32 scale);
inline void OSSetGQR4(u32 type, u32 scale);
inline void OSSetGQR5(u32 type, u32 scale);
inline void OSSetGQR6(u32 type, u32 scale);
inline void OSSetGQR7(u32 type, u32 scale);

Arguments

type	Data Types. The specifiable values are: `OS_GQR_F32, OS_GQR_S8, OS_GQR_S16, OS_GQR_U8, OS_GQR_U16`.
*`scale`*	Scaling coefficient. The specifiable values are: `OS_GQR_SCALE_* or OS_GQR_DIVIDE_*`.

Return Values

None.

Description

Sets a value to a GQR (quantization register) in the Broadway CPU. These register values are used to convert from floating-point to integer or vice versa with a paired single floating-point load/store instruction.

The type argument defines the data type used to load floating-point values from memory or store floating-point values into memory. The scale argument defines the scale factor when a value is stored into memory as an integer value. For loading a value from memory, the inverted scale factor is applied. For example, If you use OS_GQR_SCALE_4, the value will be scaled by 4 when stored, and divided by 4 when loaded.)

The Broadway CPU has 8 GQRs. Since GQR0 and GQR1 are reserved for the system, no APIs to modify them are available.

Note: OS fast cast functions use GQR2 to GQR5. If you change them after OSInitFastCast is called, such OS fast-cast functions as OSf32tos16 and OSf32tos8 will not behave correctly. In such a case, call the OSInitFastCast function again to re-initialize the four registers.

Revision History

2006/03/01 Initial version.