8.1.7 'switch' Statements

SDCC can optimize switch statements to jump tables. It makes the decision based on an estimate of the generated code size. SDCC is quite liberal in the requirements for jump table generation:

Switch statements which have large gaps in the numeric sequence or those that have too many case labels can be split into more than one switch statement for efficient code generation, e.g.:
switch (i) { 
  case 1: ... 
  case 2: ... 
  case 3: ... 
  case 4: ... 
  case 5: ... 
  case 6: ... 
  case 7: ... 
  case 101: ... 
  case 102: ... 
  case 103: ... 
  case 104: ... 
  case 105: ... 
  case 106: ... 
  case 107: ... 
}
If the above switch statement is broken down into two switch statements
switch (i) { 
  case 1: ... 
  case 2: ... 
  case 3: ... 
  case 4: ... 
  case 5: ... 
  case 6: ... 
  case 7: ... 
}
and
switch (i) { 
  case 101: ... 
  case 102: ... 
  case 103: ... 
  case 104: ... 
  case 105: ... 
  case 106: ... 
  case 107: ... 
}
then both the switch statements will be implemented using jump-tables whereas the unmodified switch statement will not be.