| Routines

2D1B: THE 'NUMERIC' SUBROUTINE

Used by the routines at OUT_SP_2, ALPHANUM, DEC_TO_FP and STK_DIGIT. This subroutine returns with the carry flag reset if the present value of the A register denotes a valid digit.
Input
A | Character code
Output
F | Carry flag reset if the character is a digit (0-9)
NUMERIC | 2D1B | CP "0" | Test against +30, the code for '0'.
| 2D1D | RET C | Return if not a valid character code.
| 2D1E | CP $3A | Test against the upper limit.
| 2D20 | CCF | Complement the carry flag.
| 2D21 | RET | Finished.