Motorola 700/800-Series User Manual

4-18

Using the 162Bug Debugger

The floating point unit (FPU) of the MC68040 microprocessor chip 
is supported in 162Bug. The 

, 

, 

, and 

 commands have 

been extended to allow display and modification of floating point 
data in registers and in memory. Floating point instructions can be 
assembled and disassembled with the 

 option of the 

 and 

 

commands.

 and 

 for floating point registers accept the floating point 

value in Double Precision Real Format or Scientific Notation.

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 or double precision, you must observe 
the following rules:

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. 

12

Byte

1234

Word

12345678

Longword

1_FF_7FFFFF

Single Precision Real Format

1_7FF_FFFFFFFFFFFFF

Double Precision Real Format

-3.12345678901234501_E+123

ScientiÞc Notation Format (decimal)