iii.3.10-ble.length.md

III.3.10 ble.<length> – branch on less than or equal to

Format	Assembly Format	Description
3E <int32>	ble target	Branch to target if less than or equal to.
31 <int8>	ble.s target	Branch to target if less than or equal to, short form.

Stack Transition:

…, value1, value2 → …

Description:

The ble instruction transfers control to target if value1 is less than or equal to value2. target is represented as a signed offset (4 bytes for ble, 1 byte for ble.s) from the beginning of the instruction following the current instruction.

The effect of a ble target instruction is identical to:

• If stack operands are integers, then: cgt followed by a brfalse target

• If stack operands are floating-point, then: cgt.un followed by a brfalse target

The acceptable operand types are encapsulated in Table 4: Binary Comparison or Branch Operations.

If the target instruction has one or more prefix codes, control can only be transferred to the first of these prefixes.

Control transfers into and out of try, catch, filter, and finally blocks cannot be performed by this instruction. (Such transfers are severely restricted and shall use the leave instruction instead; see Partition I for details).

Exceptions:

None.

Correctness:

Correct CIL shall observe all of the control transfer rules specified above and shall guarantee that the top two items on the stack correspond to the types shown in Table 4: Binary Comparison or Branch Operations.

Verifiability:

Verifiable code requires the type-consistency of the stack, locals and arguments for every possible path to the destination instruction. See §III.1.8 for more details.