Motorola MVME162 User Manual

Floating Point Support

4-17

The floating point unit (FPU) of the MC68040 microprocessor chip is 
supported in 162Bug. For MVME162Bug, the commands MD, MM, RM, and 
RS

 have been extended to allow display and modification of floating point 

data in registers and in memory. Floating point instructions can be 
assembled/disassembled with the DI option of the MD and MM commands.

Valid data types that can be used when modifying a floating point data 
register or a floating point memory location: 

When entering data in single, double, extended precision, or packed decimal 
format, the following rules must be observed:

1.

The sign field is the first field and is a binary field.

2.

The exponent field is the second field and is a hexadecimal field.

3.

The mantissa field is the last field and is a hexadecimal field.

4.

The sign field, the exponent field, and at least the first digit of the mantissa 
field must be present (any unspecified digits in the mantissa field are set 
to zero).

5.

Each field must be separated from adjacent fields by an underscore.

6.

All the digit positions in the sign and exponent fields must be present.

12

Byte

1234

Word

12345678

Longword

1_FF_7FFFFF

Single Precision Real Format

1_7FF_FFFFFFFFFFFFF

Double Precision Real Format

1_7FFF_FFFFFFFFFFFFFFFF

Extended Precision Real Format

1111_2103_123456789ABCDEF01

Packed Decimal Real Format

-3.12345678901234501_E+123

Scientific Notation Format (decimal)