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RTSD
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Releasing stack frame and returning from subroutine
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RTSD
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ReTurn from Subroutine and Deallocate stack frame
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[Syntax]
(1)RTSD src
(2)RTSD src, dest-dest2
[Operation]
(1)SP = SP + src;
PC = *SP;
SP = SP + 4;
(2)signed char i;
SP = SP + ( src - ( register_num(dest2) - register_num(dest) +1 ) * 4 );
for ( i = register_num(dest); i <= register_num(dest2); i++ ) {
tmp = *SP;
SP = SP + 4;
register(i) = tmp;
}
PC = *SP;
SP = SP + 4;
[Function]
- | This instruction rotates dest one bit to the right including the C flag. |
- | This instruction restores values for the block of registers in the range specified by dest and dest2 from the stack. |
- | The range is specified by first and last register numbers. Note that the condition (first register number ? last register number) must be satisfied. |
- | The stack pointer in use is specified by the U bit in the PSW. |
- | Registers are restored from the stack from R1 to R15: |
[Instruction Format]
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(1)RTSD src
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#UIMM:8
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(2)RTSD src, dest-dest2
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#UIMM:8
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Rd (Rd=R1~R15)
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Rd2 (Rd=R1~R15)
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[Flag Change]
- | This instruction does not affect the states of flags. |
[Description Example]
RTSD #4
RTSD #16, R5-R7