Xerox Sigma 6 Reference Manual page 42

registers Rand Rul is -2 63 and CC2 is set to 1; otherwise,
CC2 is reset to O.
Affected: (R), (Ru1 ),CC2, Trap: Fixed -point overflow
CC3,CC4
[-ED] 32-63 - Ru 1; [-ED]O_31 - R
Cond i ti on code setti ngs:
2 3 4
Two's complement of effective doubleword
0
0 0
zero
0 1 negative
0
0
positive
0
no fixed-point overflow
1 0
fixed-point overflow
If CC2 is set to 1 and the fixed-point arithmetic trap mask
(AM) is a 1, the computer traps to location X'43' after exe-
cution of LOAD COMPLEMENT DOUBLEWORD; otherwise,
the computer executes the next instruction in sequence.
Example 1, evenR field value:
Before execution
After execution
ED X'0123456789ABCDEF'
X '0123456789ABC DEF'
(R) xxxxxxxx X'FEDCBA98'
(Ru 1) xxxxxxxx
X
'76543211'
CC
xxxx xOOl
Example 2, odd R field value:
ED X'0123456789ABCDEF' X'0123456789ABCDEF'
(R) xxxxxxxx
X'FEDCBA98'
CC
xxxx
xOOl
LAD
LOAD ABSOLUTE DOUBLEWORD
(Doubleword index al ignment)
If the effective doubleword is positive, LOAD ABSOLUTE
DOUBLEWORD loads the 32 low-order bits of the effective
doubleword into register Ru 1, and then loads the 32 high-
order bits of the effective doubleword into register R. If R
is an odd value, the result in register R is the 32 high-order
bits of the effective doubleword. The condition code settings
are based on the effective doubleword, rather than the fina'!
result in register R.
If
the effective doubleword is negative, LAD forms the
64-bit two's complement of the effective doubleword, loads
the 32 low-order bits of the two's complemented doubleword
into register Ru 1, and then loads the 32 high-order bits of the
two's complemented doubleword into register R.
If R is an
odd value, the result in register R is the 32 high-order bits
of the two's complemented doubleword. The condition code
settings are based on the two's complement of the effective
doubleword, rather than the final result in register R.
Fixed-point overflow occurs if the effective doubleword is
_~3 (X'8000000000000000'), in which case the result in
34 Load/Store Instructions
registers Rand Ru 1 is -2 63 and CC2 is set to 1; otherwise,
CC2 is reset to O.
Affected: (R),(Ru 1 ),CC2, Trap: Fixed-point overflow.
CC3,CC4
IED1
32
_
63
- Rul; 1ED10_31 - R
Condition code settings:
2 3
4 Absolute value of effective doubleword
0
0 0 zero
1 0 nonzero
0
no fixed-point overflow
1
0
fixed-point overflow (sign bit on)
If CC2 is set to 1 and the fixed-point arithmetic trap mask
(AM) is a 1, the computer traps to location X'43' after exe-
cution of LOAD ABSOLUTE DOUBLEWORDi otherwise, the
computer executes the next instruction in sequence.
Example 1, even R field value:
Before execution After execution
ED X'0123456789ABCDEF'
X'0123456789ABCDEF'
(R)
xxxxxxxx X'01234567'
(Ru 1) xxxxxxxx X'89ABCDEF'
CC
xxxx xOl0
Example 2, even R field value:
ED X'FEDCBA9876543210'
X'FEDCBA9876543210'
(R)
xxxxxxxx X'01234567'
(Ru 1) xxxxxxxx
X'89ABCDFO'
CC xxx x x010
Example 3, odd R field value:
ED
(R)
CC
X'0123456789ABCDEF' X '0123456789ABCDEF'
xxxxxxxx X'01234567'
xxxx xOl0
LS LOAD SELECTIVE
(Word index alignment
Register Ru1 contains a 32-bit mask. If R is an even value,
LOAD SELECTIVE loads the effective word into register R
in those bit positions selected by a 1 in correspondi ng bit
positions of register Ru 1. The contents of register R are not
affected in those bit positions selected by a 0 in correspond-
ing bit positions of register Ru 1.
If
R is an odd value, LS logically ANDs the contents of
register R with the effective word and loads the result into
register R.
If corresponding bit positions of register Rand
the effective word both contain l's, a 1 remains in register
Ri
otherwise, a 0 is placed in the corresponding bit position
of register R.
Affected: (R), CC3, CC4
If R is even, [EWn(RulUu[(R)n(Rul)]-R
If R is odd, EWn(R)-R