Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
Alloc
Allocate Memory
Function Call
48H
Returns a pointer to a free block of memory that has the re-
quested size in paragraphs,
Entry Conditions:
AH = 48H
BX
= size of memory to be allocated, in paragraphs
Exit Conditions:
Carry set:
BX = maximum size that could be allocated, in paragraphs
(if the requested size was
not available)
AX10 = pointer to the allocated memory
Carry not set:
Error Returns:
AX = 8
Not enough memory. The largest available free block is
smaller than that requested or there is no free block.
Arena trashed. The internal consistency
of the memory
arena has been destroyed. This is due
to a user program
changing memory that does not belong
to it.
AX = 7
Example:
Alloc equ 48H
mov bx, 51ze
mov ah, Fllloc
Int 21 H
123

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200