Slot Inst | 6 3 | 6 2 | 6 1 | 6 0 | 5 9 | 5 8 | 5 7 | 5 6 | 5 5 | 5 4 | 5 3 | 5 2 | 5 1 | 5 0 | 4 9 | 4 8 | 4 7 | 4 6 | 4 5 | 4 4 | 4 3 | 4 2 | 4 1 | 4 0 | 3 9 | 3 8 | 3 7 | 3 6 | 3 5 | 3 4 | 3 3 | 3 2 | 3 1 | 3 0 | 2 9 | 2 8 | 2 7 | 2 6 | 2 5 | 2 4 | 2 3 | 2 2 | 2 1 | 2 0 | 1 9 | 1 8 | 1 7 | 1 6 | 1 5 | 1 4 | 1 3 | 1 2 | 1 1 | 1 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
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Format x24 - 24 bit(s) | 0 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
DIU | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | ||||||||||||||||||||||||||||||||||||||||||||||||
s | 3 | 2 | 1 | 0 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
op2 | 3 | 2 | 1 | 0 |
DIU as, 0..240
extern void XT_DIU(const int * s, immediate i);
(please consult the Xtensa ® Instruction Set Architecture Reference Manual for any cross references and additional information)
DIU
uses the virtual address to choose a location in the data cache and unlocks the chosen line. The purpose of DIU is to remove the lock created by a DPFL instruction. The method for mapping the virtual address to a data cache location is implementation-specific. This instruction is primarily useful for unlocking the entire data cache. Xtensa ISA implementations that do not implement cache locking must raise an illegal instruction exception when this opcode is executed.
To unlock a specific cache line if it is in the cache, use the DHU instruction.
DIU
forms a virtual address by adding the contents of address register as
and a 4-bit zero-extended constant value encoded in the instruction word shifted left by four. Therefore, the offset can specify multiples of 16 from zero to 240. The virtual address chooses a cache line without translation and without raising the associated exceptions.
Because the organization of caches is implementation-specific, the operation section below specifies only a call to the implementation's dindexunlock
function.
DIU is a privileged instruction.
if CRING != 0 then Exception (PrivilegedCause) else vAddr ← AR[s] + (024||imm4||04) dindexunlock(vAddr) endif