z80 » Variables
TI has given us the addresses of most of the math routines. You can use
these routines to make some useful math programs. Let me begin by saying
that if you're going to be making programs that do huge amounts of
calculation, you probably want to go ahead and just use TI-BASIC. Asm is
a lot faster most of the time but it's a heck of a lot easier to make a math
program in TI-BASIC than in asm. Just look at the
TI-BASIC versus Asm Chart, you can see that
it's easier to add, subtract, multiply, divide, and store numbers in
TI-BASIC. Just storing
A is somewhere
around 50 bytes in asm but only 3 or 4 in TI-BASIC.
Before beginning, make sure you have the include file ti86math.inc. It's also included in Includes.zip. This include file will give you the equates for the many Math Functions TI has given us. The comments in the file explain the inputs and outputs of each function.
You can pretty much teach yourself this section. All you have to do is look at some source and you'll get the basic idea. Let's try letting the uesr input a number and display the square root of it. Download it to see what it looks like in action.
#include "ti86asm.inc" ;normal include file with ; common ROM calls #include "ti86math.inc" ;contains math function ; equates _formDisp =$515b _ioprompt =$c324 _asap_ind =$d623 .org _asm_exec_ram call _clrScrn ;clear screen & text memory ld bc,0*256+0 ;row 0, col 0 ld (_curRow),bc ld hl,string ;string to prompt with call input ;input number and store ; in OP1 call _SQRoot ;$54ac - op1 = square root ; of op1 jp _formDisp ;$515b - displays op1 right ; justified big numbers ;aka _dispOP1 input: ;14 byte routine to input ; numbers ;ti was nice enough to ; give us the basics of ; this routine ld de,_ioprompt ;$c324 - string storage for ; display when prompted call _mov10b ;$427b - move 10 bytes from ; hl to de ld a,$0d ;type of input ;$0d - value :$0c - string ld (_asap_ind),a ;$d623 - tell ti86 what kind ; to be inputted jp _exec_pg3 ;$5714 - ti86 os input ; routine of type ; (_asap_ind) with all ti-os ; key handler routines ;inputted value/string stored ; in op1 string: .db "number? ",0 ;string to prompt with .end
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Absolute Addressing // Binary Coded Decimal // Creating Variables // External Levels // _FindSym // Messing with Variable Data // OP Math // TI-OS Variable Manipulation // Variable Name Format // VAT Searches