what means for this powerpc instruction?

Question

this instruction is from powerpc uboot .

lis r3 CONFIG_SYS_DEFAULT_IMMR@h

particularly "@h" what mean?

another insruction:

lwz r4,0(r3)

particularly "0(r3)" what mean?

thanks!

Answer 1

lis r3,CONFIG_SYS_DEFAULT_IMMR@h

Loads the high (upper) halfword (16 bits) of the immediate operand into the upper halfword of r3. The @h suffix is used to specify the high halfword of CONFIG_SYS_DEFAULT_IMMR.

For example, if CONFIG_SYS_DEFAULT_IMMR is equal to 0x12345678 the above instruction would load 0x1234 into the upper halfword of r3.

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lwz r4,0(r3)

Loads a word (32 bits) from the effective address (r3+0) into r4. If r4 is a 64-bit register it would additionally clear the upper word of r4.