Re: Ada case-statement

["Dan'l Miller" <optikos@verizon.net>]

On Wednesday, March 14, 2018 at 7:57:57 PM UTC-5, Robert Eachus wrote:
> The compiler probably will convert to an if statement, 

For dense case statements that utilize all or most of an enumerated type's enumerated values, a jump table is the most likely on most processors to achieve O(1) growth [instead of if-statement-based O(n) growth, where n is the quantity of enumerated values in an enumerated type].

https://stackoverflow.com/questions/39875452/assembly-jump-branch-lookup-tables-instead-of-lots-of-cmp-je

In IA-32, a jump table can be transliterated fairly directly from a case-statement over a dense utilization of an enumerated type.  Indeed, if the quantity of enumerated values in the enumerated type is small enough, a case statement that sparsely utilizes only a relative few of the enumerated values also can be transliterated to a jump table, where the unmentioned enumerated values conflate to unhandled case.
jmp  [jump_table + si]
jump_table:
   dw   .F_1,  .F_2, ...