dup_x1

Duplicate top operand stack word and put two down

Bytecode

Type Description
u1 dup_x1 = 0x5A (90)

Stack ..., word2, word1 => ..., word1, word2, word1

Description
Duplicates the top item on the stack and inserts the duplicate below the second-from-top item. Both items must be single-word items.

The top word on the operand stack is duplicated and the copy inserted two words down in the operand stack.

The dup_x1 instruction must not be used unless each of word1 and word2 is a word that contains a 32-bit data type.

Except for restrictions preserving the integrity of 64-bit data types, the dup_x1 instruction operates on untyped words, ignoring the types of the data they contain.

This instruction cannot be used if either of item1 or item2 are two-word items. To duplicate a two-word item (a long or a double) you must use dup2, dup2_x1 or dup2_x2.