MB86831 Datasheet, PDF (57/82 Pages) Fujitsu Component Limited. – 32-bit Embedded Controller

MB86830 Series
available b writing the parameter to be passed to the “out” register and using a procedure call to decrement the
window pointer by one. The passed parameter remains in the “in“ registers in the current register window and can
be used by that subroutine.
Register windows improve the performance of embedded applications. This is because these windows serve as
the local variable caches for storing interrupt, subroutine, context, or operating system variables without increasing
overhead. In addition, the code size of programs can be reduced by using an efficient method of executing proce-
dure linkage without optimizing the code using an inlining compiler.
The register file consists of 4-port registers: 3-port read and 1-port write registers. Even the store instruction can
therefore be executed in one cycle, which requires three operands to be read from the register file.
The control and status registers are divided into those defined in the SPARC architecture and those mapped into
the alternate address space for controlling the functions of peripheral devices.
• General register composition
W7
WIM
outs
W1
locals
ins
outs
locals
ins
W0
restore
locals
outs
ins
locals
W6
outs
save
CWP
ins
outs
ins
W2
locals
ins
W4
ins
locals
outs
W5
locals
outs
outs
locals
ins
W3
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