Reference Manual

PMAC 2 Software Reference
262 PMAC On-Line Command Specification
M{constant}->X/Y:{address}
Function
Short Word M-Variable Definition
Scope
Global
Syntax
M{constant}[..{constant}]->
X[:]{address},{offset}[,{width}[,{format}]]
M{constant}[..{constant}]->
Y[:]{address},{offset}[,{width}[,{format}]]
where:
• {constant} is an integer from 0 to 1023 representing the number of the M-variable;
• the optional second{constant} must be at least as great as the first {constant} – it
represents the number of the end of the range;
• {address} is an integer constant from 0 to 65,535 ($0 to $FFFF if specified in hex);
• {offset} is an integer constant from 0 to 23, representing the starting (least
significant) bit of the word to be used in the M-variable(s), or 24 to specify the use of all
24 bits;
• {width} (optional) is an integer constant from the set {1, 4, 8, 12, 16, 20, 24},
representing the number of bits from the word to be used in the M-variable(s); if
{width} is not specifed, a value of 1 is assumed;
• {format} (optional) is a letter from the set [U, S, D, C], specifying how PMAC is to
interpret this value: (U=Unsigned integer, S=Signed integer, D=Binary-coded Decimal,
C=Complementary binary-coded decimal); if {format} is not specified, U is assumed.
Note:
No spaces are permitted between the M-variable name and the arrow
double character in this command.
Remarks
This command causes PMAC to define the specified M-variable or range of M-variables to
point to a location in one of the two halves (X or Y) of PMAC’s data memory. In this form,
the variable can have a width of 1 to 24 bits and can be decoded several different ways, so the
bit offset, bit width, and decoding format must be specified (the bit width and decoding
format do have defaults.
The definition consists of the letter X or Y, an optional colon (:), the word address, the
starting bit number (offset), an optional bit width number, and an option format-specifying
letter.
Legal values for bit width and bit offset are inter-related. The table below shows the possible
values of {width}, and the corresponding legal values of {offset} for each setting of
{width}.
{width} {offset}
1 0 – 23
4 0,4,8,12,16,20
8 0,4,8,12,16
12 0,4,8,12
16 0,4,8
20 0,4