1. xerox 560 computer system - The UK Mirror Service

Example 2, odd R field value:Before executionAfter executionED X'0123456789ABCDEP X'0123456789ABCDEF'(R) xxxxxxxx X'FEDCBA98'CC xxxx x001LADLOAD ABSOLUTE DOUBLEWORD(Doubleword index alignment)of LOAD ABSOLUTE DOUBLEWORDi otherwise, the BPexecutes the next instruction in sequence.Example 1, even R field value:Before executionAfter executionED X'0123456789ABCDEF' X'0123456789ABCDEF'(R) xxxxxxxx X'01234567'(Ru1) = xxxxxxxx X'89ABCDEF'CC xxxx xOlOIf the effective doubleword is positive, LOAD ABSOLUTEDOUBLEWORD loads the 32 low-order bits of the effectivedoubleword into register Ru1, and then loads the 32 highorderbits of the effective doubleword into register R. If R isan odd value, the result in register R is the 32 high-orderbits of the effective doubleword. The condition code settingsare based on the effective doubleword, rather thanthe final result in register R.If the effective doubleword is negative, LAD forms the64-bit two's complement of the effective doubleword, loadsthe 32 low-order bits of the two's complemented doublewordinto register Ru 1, and then loads the 32 high-orderbits of the two's complemented doubleword into register R.If R is an odd value, the result in register R is the 32 highorderbits of the two's complemented doubleword. The conditioncode settings are based on the two's complement of.LL __ CC_ ... - _I II I .1.1 .1,... I I ••11'1:: I::1II::~IIVl:: UUUUII::VVUIU, IUHH:::r IrIun rne nnol resulT Inregister R.Fixed-point overflow occurs if the effective doubleword is-2 63 (X'8000000000000000'), in which case the result inregisters Rand Rul is -263 and CC2 is set to 1; otherwise,CC2 is reset to O.Affected: (R), (Ru 1),CC2,CC3,CC4Trap: Fixed-point overflowExample 2, even R field value:Before executionAfter executionED X' FEDCBA9876543210' X' FEDCBA987654321 0'(R) xxxxxxxx X'01234567'(Rul) = xxxxxxxx X'89ABCDFO'CC xxxx xOlOExample 3, odd R field value:Before executionAfter executionED - X'G.23456789ADCDEF X'G.23456789ADCDEF(R) xxxxxxxx X'01234567'CC xxxx xOlOLASLOAD AND SET(Word index alignment)IED1 32_ 63-Ru1i IEDI 0_ 31-RCondition code settings:2 3 4 Absolute value of effective doubleword- 0 0 0 Zeroo Nonzero- 0 No fixed-point overflowoFixed-point overflow (sign bit on)If CC2 is set to 1 and the fixed-point arithmeti c trap mask(AM) is a 1, the BP traps to location X'43' after executionLOAD AND SET loads the effective word into R. Ifthe effective address is equal to or greater than 16, aone is stored in the sign position of the effective location.If the effective address is equal to or less than 15(effective location is a general register), the sign bitremains unchanged. This instruction is used to interlockmultiple processors from the simultaneous execution ofcertai n secti ons of code or from the si mu I taneous accessto certain tables.Affected: (R), CC3, CC4EW-R1 -EW O ' if EA ~ 16Load/Store Instructions 53