| Routines

2D22: THE 'STK-DIGIT' SUBROUTINE

Used by the routines at DEC_TO_FP and INT_TO_FP. This subroutine simply returns if the current value held in the A register does not represent a digit but if it does then the floating-point form for the digit becomes the 'last value' on the calculator stack.
Input
A | Character code
Output
F | Carry flag reset if the character is a digit (0-9)
STK_DIGIT | 2D22 | CALL NUMERIC | Is the character a digit?
| 2D25 | RET C | Return if not.
| 2D26 | SUB "0" | Replace the code by the actual digit.
This routine continues into STACK_A.