Routines 
Prev: 3004  Up: Map 
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 +03 by the routines at BEEP, NEXT_LOOP, CIRCLE, DRAW, CD_PRMS1, S_RND, PRINT_FP, series, n_mod_m, int, exp, ln, get_argt, cos, sin, atn, asn and acs. It is also called indirectly via fp_calc_2.
This subroutine simply changes the sign of the subtrahend and carries on into addition.
Note that HL points to the minuend and DE points to the subtrahend. (See addition for more details.)


subtract  300F  EX DE,HL  Exchange the pointers.  
3010  CALL negate  Change the sign of the subtrahend.  
3013  EX DE,HL  Exchange the pointers back and continue into addition. 
Prev: 3004  Up: Map 