Reference Manual

PMAC 2 Software Reference
34 PMAC I-Variable Specifiation
I20 Data Gathering Selection Mask
Range
$000000 .. $FFFFFF (0 .. 16,777,215)
Units
none
Default
0
Remarks
I20 is a 24-bit variable that controls which of the 24 potential data sources (as specified by
I21 to I44) will be gathered when gathering is performed. If bit 0 (least significant bit) is
1, the 1st source (specified by I21) will be gathered; if it is 0, it will not be. Bit 1 controls
the 2nd source (I22), and so on, to bit 23, which controls the 24th source (I44).
With I9 at 2 or 3, the value of this variable will be reported back to the host in hexadecimal
form, which is the more convenient form for understanding the value.
Note:
Normally this parameter is controlled automatically by the PMAC
Executive Program’s Gathering and Tuning routines.
Example
With I20=7, only the addresses specified by I21, I22, & I23 will be gathered
With I20=$FF (255), the addresses specified by I21-I28 will be gathered
With I20=$300 (768), the addresses specified by I29 and I30 will be gathered
With I20=$FFFFFF (8,388,607), the addresses specified by I21-I44 will be gathered
See Also
Data Gathering (Analysis Features)
On-line commands GATHER, ENDGATHER, <CTRL-E>
I-variables; I19, I21-I44.
I21 Data Gathering Source 1 Address
Range
$000000 .. $FFFFFF (0 .. 16,777,215)
Units
Modified PMAC addresses
Default
0
Remarks
I21 specifies the address of the first data item to be gathered. This address is usually given
in hexadecimal (i.e. preceded by a ‘$’).
The specification is twenty-four bits – six hex digits. The lowest 16 bits – 4 hex digits –
represent the actual word address in PMAC’s memory and I/O space.
The highest two bits specify which part of the double word at that address is to be gathered
(the Motorola DSP56000 has a double memory space – X and Y – to supply its dual data
buses). If both of these bits are 0 – first hex digit is 0 – the Y word will be gathered; if the
higher bit is 0 and the second bit is 1 – first hex digit is 4 – the X word will be gathered; if
the higher bit is 1 – first hex digit is 8 or greater – both the X and Y words will be gathered
as a long (double) word. In the case of a long word, it does not matter to PMAC what the
second bit is, but the PMAC PC-Executive Program uses this bit to note whether this word
is a fixed-point (0) or floating-point (1) value.
With I9 at 2 or 3, the value of this variable will be reported back to the host in hexadecimal
form, which is the more convenient form for understanding the value.
Note:
Normally this parameter is controlled automatically by the PMAC
Executive Program’s Gathering and Tuning routines.