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EV80C196KB Microcontroller Evaluation Board User's Manual -37-
DISPLAYING AND MODIFYING PROGRAM VARIABLES
iECM-96 provides commands to display and modify program variables in several
formats. In addition to simple variables such as bytes and words, more complicated
variables such as reals and character strings are supported. iECM-96 commands
allow variables to be displayed or initialized either individually or as regions of mem-
ory which contain variables of the given type.
Supported Data Types
BYTE
A BYTE is an eight-bit variable. No alignment rules are enforced for BYTE variables.
CHAR
A CHAR is a special case of a BYTE. CHAR variables are displayed as ASCII char-
acters.
WORD
A WORD is a 16-bit variable. The address of a WORD is the address of its least
significant byte. A WORD must start at an even byte address.
DWORD
A DWORD is a 32-bit variable. The address of a DWORD is the address of its least
significant byte. A DWORD must always start at an even byte address. If a DWORD
variable is to be accessed as a register by an 8096 instruction then a more restric-
tive alignment rule is enforced: it must start at an address which is evenly divisible
by 4. This more restrictive alignment rule will only apply to iECM-96 commands
when using the single line assembler.
REAL
A REAL is a 32-bit binary floating point number which conforms to the FPAL96
definition. The 32 bits contain a sign bit, an 8-bit exponent field, and a 23-bit fraction
field. iECM-96 commands use standard scientific notation to deal with REAL num-
bers
Note that the FPAL96 has special representations for +infinity and for NaN's
(Not a Number--used to signal error conditions) if iECM-96 detects one of these
special values it will output an appropriate text string instead of trying to display the
value in scientific notation.
STACK
A STACK variable is a 16-bit variable which resides in the system stack. The ad-
dresses of stack variables (cstack7addr> are taken to be relative to the current
stack pointer and must be word alrgned.
STRING
A STRING is a sequence of ASCII characters which are terminated by the NUL
character. The ASCII character NUL has the binary value of zero.
In addition to supporting access to variables of the above types, iECM-96 also
provides commands to access the special program variables PC (program counter),
PSW (program status word) and SP (stack pointer). These commands are dis-
cussed at the end of this section under the heading "Processor Variables".
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