FPREG

Coprocessor stack register element.

Type

ULONG  losig
ULONG  hisig
USHORT signexp

C Declaration Method

typedef struct

Fields

losig

Low 32-bits of the significand.

The low 32-bits of the number's significant digits are held in the lower part of the significand field.

hisig

High 32-bits of the significand.

The high 32-bits of the number's significant digits are held in the higher part of the significand field.

signexp

Sign and exponent.

The exponent field (bits 64-78) locates the binary point within the significand field (bits 0-63).

The 1-bit sign field (bit 79) indicates whether the number is positive or negative.

Comment

A floating point register is 80 bits wide and consists of three fields. The following graphic shows the layout of the floating point register:

79  78         64 63                                     0
┌───┬────────────┬───────────────────────────────────────┐
│   │            │             Significand               │
└─┬─┴──────┬─────┴───────────────────────────────────────┘
  │        │
  │        Exponent
 Sign