| Routines

34F9: THE 'GREATER THAN ZERO' OPERATION (offset +37)

Used by the routine at compare. The address of this routine is found in the table of addresses. It is called via the calculator literal +37 by the routines at NEXT_LOOP, PRINT_FP, ln, get_argt and to_power. This subroutine returns a 'last value' of one if the present 'last value' is greater than zero and zero otherwise. It is also used by other subroutines to 'jump on plus'.
Input
HL | Address of the first byte of the number
greater_0 | 34F9 | CALL TEST_ZERO | Is the 'last-value' zero?
| 34FC | RET C | If so, return.
| 34FD | LD A,$FF | Jump forward to less_0 but signal the opposite action is needed.
| 34FF | JR SIGN_TO_C