5
INSTRUCTION SET
42
EPSON
S1C33 FAMILY C33 PE CORE MANUAL
5
.
14
.
2
Delayed Branch Instructions
The C
33
PE Core uses pipelined instruction processing, in which instructions are executed while other instructions
are being fetched. In a branch instruction, because the instruction that follows it has already been fetched when it
is executed, the execution cycles of the branch instruction can be reduced by one cycle by executing the prefetched
instruction before the program branches. This is referred to as a delayed branch function, and the instruction
executed before branching (i.e., the instruction at the address next to the branch instruction) is referred to as a
delayed slot instruction.
The delayed branch function can be used in the instructions listed below, which in mnemonics is identified by the
extension
“
.d
”
added to the branch instruction name.
Delayed branch instructions
jrgt.d jrge.d jrlt.d jrle.d jrugt.d jruge.d jrult.d
jrule.d jreq.d jrne.d call.d jp.d ret.d jpr.d
Delayed slot instructions
It is necessary that the delayed slot instructions satisfy all of the following conditions:
•
1
-cycle instruction
•
Do not access memory
•
Not extended by an
ext
instruction
The instructions listed below can be used as delayed slot instructions:
ld.b
%rd
,
%rs
ld.ub
%rd
,
%rs
ld.h
%rd
,
%rs
ld.uh
%rd
,
%rs
ld.w
%rd
,
%rs
ld.w
%rd
,
sign6
add
%rd
,
%rs
add
%rd
,
imm6
add
%sp,
imm10
adc
%rd
,
%rs
sub
%rd
,
%rs
sub
%rd
,
imm6
sub
%sp,
imm10
sbc
%rd
,
%rs
cmp
%rd
,
%rs
cmp
%rd
,
sign6
and
%rd
,
%rs
and
%rd
,
sign6
or
%rd
,
%rs
or
%rd
,
sign6
xor
%rd
,
%rs
xor
%rd
,
sign6
not
%rd
,
%rs
not
%rd
,
sign6
srl
%rd
,
%rs
srl
%rd
,
imm5
sll
%rd
,
%rs
sll
%rd
,
imm5
sra
%rd
,
%rs
sra
%rd
,
imm5
sla
%rd
,
%rs
sla
%rd
,
imm5
rr
%rd
,
%rs
rr
%rd
,
imm5
rl
%rd
,
%rs
rl
%rd
,
imm5
swap
%rd
,
%rs
swaph
%rd
,
%rs
ld.c
%rd
,
imm4
ld.c
imm4
,
%rs
Note
: Unless the above conditions are satisfied, the instruction may operate unstably. Therefore, it is
prohibited to use such instructions as delayed slot instructions.
Содержание S1C33 Series
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