7-40
Seiko Epson Corporation
S1C17 CORE MANUAL
(REV. 1.2)
jpr %rb
jpr.d %rb
Function
Unconditional PC relative jump
Standard) pc
←
pc + 2 +
rb
Extension 1) Unusable
Extension 2) Unusable
Code
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 1 0 1 0 0 0
r b
jpr
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0 0 0 0 0 0 0 1 1 1 0 0 0
r b
jpr.d
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Flag
IL IE C V Z N
– – – – – –
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Mode
Signed PC relative
CLK
jpr
Three cycles
jpr.d
Two cycles (when a one-cycle delayed slot instruction follows), Three cycles (other)
Description
(1) Standard
jpr %rb
The content of the
rb
register is added to the PC (PC + 2), and the program branches to that
address. The LSB of the
rb
register is ignored and is always handled as 0.
(2) Delayed branch (d bit (bit 7) = 1)
jpr.d %rb
For the
jpr.d
instruction, the next instruction becomes a delayed slot instruction. A delayed
slot instruction is executed before the program branches. Interrupts are masked in intervals
between the
jpr.d
instruction and the next instruction, so no interrupts occur.
Example
jpr %r0
; pc
←
pc + 2 + r0
Caution
When the
jpr.d
instruction (delayed branch) is used, be careful to ensure that the next instruction
is limited to those that can be used as a delayed slot instruction. If any other instruction is executed,
the program may operate indeterminately. For the usable instructions, refer to the instruction list in
the Appendix.