Renesas M32R-FPU - Manual (Page 155)

3
3-117 M32R-FPU Software Manual (Rev.1.01)
UNLOCK UNLOCK
load/store instruction
Store unlocked
[Mnemonic]
UNLOCK Rsrc1,@Rsrc2
[Function]
Store unlocked
if ( LOCK == 1 ) { * ( int *) Rsrc2 = Rsrc1; }
LOCK = 0;
[Description]
When the LOCK bit is 1, the contents of Rsrc1 are stored at the memory location specified by
Rsrc2. When the LOCK bit is 0, store operation is not executed. The condition bit (C) is un-
changed.
This instruction clears the LOCK bit to 0 in addition to the simple storage operation.
The LOCK bit is internal to the CPU and cannot be accessed except by using the LOCK and
UNLOCK instructions.
The user cannot directly read or write to this bit.
The LOCK bit is internal to the CPU and is the control bit for receiving all bus right requests
from circuits other than the CPU.
Refer to the Users Manual for non-CPU bus right requests, as the handling differs according to
the type of M
[EIT occurrence]
Address exception (AE)
[Encoding]
src1 0010 UNLOCK Rsrc1,@Rsrc2 src2 0101
INSTRUCTIONS
3.2 Instruction description