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 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
L16UI | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
t | 3 | 2 | 1 | 0 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
s | 3 | 2 | 1 | 0 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
imm8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
L16UI at, as, 0..510
extern unsigned short XT_L16UI(const unsigned short * p, immediate i);
(please consult the Xtensa ® Instruction Set Architecture Reference Manual for any cross references and additional information)
L16UI
is a 16-bit unsigned load from memory. It forms a virtual address by adding the contents of address register as
and an 8-bit zero-extended constant value encoded in the instruction word shifted left by 1. Therefore, the offset can specify multiples of two from zero to 510. Sixteen bits (two bytes) are read from the physical address. This data is then zero-extended and written to address register at
.
If the Region Translation Option or the MMU Option is enabled, the virtual address is translated to the physical address. If not, the physical address is identical to the virtual address. If the translation or memory reference encounters an error (for example, protection violation or non-existent memory), the processor raises one of several exceptions .
Without the Unaligned Exception Option , the least significant address bit is ignored; a reference to an odd address produces the same result as a reference to the address minus one. With the Unaligned Exception Option, such an access raises an exception.
vAddr ← AR[s] + (023||imm8||0) (mem16, error) ← Load16(vAddr) if error then EXCVADDR ← vAddr Exception (LoadStoreErrorCause) else AR[t] ← 016||mem16 endif