7
MC68020/MC68030
MC68882
-iC]-{~-l-~-l-~:l
L.__-I I____l t 1
Figure 7-19. MC68882 External-to-Register Instruction Dialog
The operation boxes that are marked
"R'"
and "'W" indicate an operand read or write cycle,
respectively, by the MPU. Those operand transfer boxes that are shaded are optionally
executed, depending on the size and location of the source operand. For example, none
of the shaded boxes are executed for source operands that reside in the MPU registers.
Also, note that the FMOVECR instruction, while it is an opclass 010 instruction, uses the
register-to-register protocol described in 7.5.1.1 REGISTER-TO-REGISTER (OPCLASS 000}.
7.5.1.3 REGISTER-TO-EXTERNAL(OPCLASS 011}. This dialog is utilized onlyforthe move
from floating-point data register instruction. The MC68881 dialog for this instruction type,
which also applies to the MC68882 except when the data format is single, double, or
extended, is shown in Figure 7-20. The first primitive returned depends on the destination
MC68020/MC68030
N~C6~8~,1/MCSB882
~ ....... A
_ ~ ,~
W t R t W s R I W ]
( , ! i
L t t I
L-- --J L_ _.,J
J
0NLY ~F A 0YNAM~: k FAir0, ~s usEo
Figure 7-20. MC68881/MC68882 Register-to-External Instruction Dialog
FREESCALE
7-24
MC68881/MC68882 USER'S MANUAL
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