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System/370 Model 168 (cont'd)
To Alter (Store in) General Registers
1.
Perform steps 1 through 7 above.
2.
Set MANUAL ENTRY SELECT to MCDR.
3.
Make certain the cursor is underiining the first byte to be changed. Enter the
data desired by pressing the data keys. In case of error, press the cursor
advance key
=>
until wraparound occurs, then return to the byte desired and
enter the correct data.
4.
Press STORE. Four bytes (right half of MCDR) are loaded into the general
register selected.
5.
Press DISPLAY to verify the load operation.
6.
Restore CRT MODE SELECT to OP.
7.
Press START to resume processing.
To Display Current PSW
1.
If the manual light is not on, press STOP.
2.
Set CRT MODE SELECT to CEo The PSW is displaved in portions. The last
portion (bits 40·63) of the instruction address is directly displayed on the
right side of the CRT, in the space designated IC. The entire first word (less
the interruption code). as well as bits 32·39 (first portion of secc'1d half of
current PSW) may
be
seen in image A3 of the indicator viewer.
3.
Restore CRT MODE SELECT to OP when processing is to continue.
To Alter (Load) Current PSW
1.
Press STOP. Manual light turns on.
2.
Set CRT MODE SELECT to CEo
3.
Set MANUAL ENTRY SELECT to MCDR.
4.
Enter the PSW data by pressing the data "eys; the cursor indicates what is
actually entered at a specified location.
5.
When all eight bytes of the MCDR are set as desired in the new current
PSW, press SET PSW. Verify change by displaying current PSW. (The only
portion not displayed is the interruption code, which should be zero.)
6.
Restore CRT MODE SELECT to OP position.
7.
Press START to resume processing.
To Display Main Storage
The CRT displays eight bytes, starting with the real location addressed.
1.
Press STOP. Manual light turns on.
2.
Set CRT MODE SELECT to CEo
3.
Set STORAGE SELECT to MAIN STOR.
4.
Set MANUAL ENTRY SELECT to MCAR to enter the real addra,s.
5.
Press the cursor advance key
=>
until the cursor underscores the second byte
in MCAR. (The first byte is ignored.)
6.
Enter a 6-digit hex address by pressing the data keys. As each key is pressed,
the appropriate digit appears in the MCER. As every second digit completes
a byte, that byte appears in the MCAR and the cursor advances to the next
byte.
7.
Press DISPLAY. Eight bytes of storage are displayed at MCDR on the CRT
display. To dispiay the next doubleword of main storage, proceed with step
8.
8.
Press ADV ADDRESS, then press DISPLAY. ("Blinking" bytes denote bad
parity. Press CHECK RESET to clear pending errors.)
9.
Restore CRT MODE SELECT to OP.
10.
Press START to resume processing.
Page 3-19
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