IBM SA14-2339-04 Manual Do Utilizador

Instruction Set

Load String Word Immediate

lswi
Load String Word Immediate

EA

←

(RA|0)

if NB = 0 then

CNT

←

32

else

CNT

←

NB

n

←

CNT

R

FINAL

←

((RT + CEIL(CNT/4) – 1) % 32)

r

←

RT – 1

i

←

0

do while n > 0

if i = 0 then

r

←

r + 1

if r = 32 then

r

←

0

if ((r

≠

RA)

∨

(r = R

FINAL

)) then

(GPR(r))

←

0

if ((r

≠

RA)

∨

(r = R

FINAL

)) then

(GPR(r)

i:i+7

)

←

MS(EA,1)

i

←

i + 8

if i = 32 then

i

←

0

EA

←

EA + 1

n

←

n – 1

An effective address (EA) is determined by the RA field. If the RA field contains 0, the EA is 0.
Otherwise, the EA is the contents of register RA.

The NB field specifies the byte count CNT. If the NB field contains 0, the byte count is CNT = 32.
Otherwise, the byte count is CNT = NB.

A series of CNT consecutive bytes in main storage, starting at the EA, are loaded into CEIL(CNT/4)
consecutive GPRs, four bytes per GPR, until the byte count is exhausted. Bytes are loaded into
GPRs; the byte at the lowest address is loaded into the most significant byte. Bits to the right of the
last byte loaded into the last GPR are set to 0.

The set of loaded GPRs starts at register RT, continues consecutively through GPR(31), and wraps to
register 0, loading until the byte count is exhausted, which occurs in register R

FINAL

. Register RA is

not altered (unless RA = R

FINAL

, an invalid form of this instruction). Bytes which would have been

loaded into register RA are discarded.

If instruction bit 31 contains 1, the contents of CR[CR0] are undefined.

• RT and subsequent GPRs as described above.

RT, RA, NB

0

6

11

16

21

31