Editing SPARC (section)

====Large constants====
As the instruction opcode takes up some bits of the 32-bit instruction word, there is no way to load a 32-bit constant using a single instruction. This is significant because addresses are manipulated through registers and they are 32-bits. To ease this, the special-purpose {{code|SETHI}} instruction copies its 22-bit immediate operand into the high-order 22 bits of any specified register, and sets each of the low-order 10 bits to 0. In general use, SETHI is followed by an or instruction with only the lower 10 bits of the value set. To ease this, the assembler includes the {{code|%hi(X)}} and {{code|%lo(X)}} macros. For example:<ref name=ncsu/>

 sethi %hi(0x89ABCDEF),%L1       !sets the upper 22 bits of L1
 or    %L1,%lo(0x89ABCDEF),%L1   !sets the lower 10 bits of L1 by ORing

The hi and lo macros are performed at assembly time, not runtime, so it has no performance hit yet makes it clearer that L1 is set to a single value, not two unrelated ones. To make this even easier, the assembler also includes a "synthetic instruction", {{code|set}}, that performs these two operations in a single line:

 set   0x89ABCDEF,% L1

This outputs the two instructions above if the value is larger than 13 bits, otherwise it will emit a single {{code|ld}} with the value.<ref name=ncsu/>