This file allows allocation and deallocation of memory using calls to BIOS. Usage: n ALLOCATE: <name> where n is the requested memory size in paragraphs ( ie. n=number of bytes /16 ) subsequent usage of <name> leaves the segment address of the allocated memory. \ ALLOCATE MEMORY 5 /15/88VISA MEMORY.BLK CAPS @ CAPS OFF 2 4 THRU CAPS ! $1000 FOR.ME \ MORE MEMORY ALLOCATION 5 /15/88CODE FOR.ME (S n -- ) \ n=number of paragraphs CS PUSH ES POP $4A # AH MOV $21 INT BX POP NEXT END-CODE CODE allocate.memory (S n -- a|e f ) \ n=number of paragraphs $48 # AH MOV $21 INT AX PUSH $73 IF TRUE # BX MOV ELSE BX BX XOR THEN NEXT END-CODE CODE deallocate (S seg -- e F| T ) \ pass segment to release ES DX MOV BX ES MOV $49 # AH MOV $21 INT $73 IF AX PUSH TRUE # BX MOV ELSE BX BX XOR THEN NEXT END-CODE \ MORE MEMORY ALLOCATION 5 /15/88: ALL.ERROR ( err# -- ) ." Memory allocate error# " . QUIT ; : ALLOCATE: (S n -- ) \ see screen 0 for usage 1 ?ENOUGH allocate.memory IF ( error) ALL.ERROR ELSE CONSTANT THEN ; : [ALL] ( n -- ) >R allocate.memory IF ( error ) ALL.ERROR THEN R> ! ; : [ALLOCATE:] ' >BODY [COMPILE] LITERAL COMPILE [ALL] ; IMMEDIATE \ DEALLOCATE MEMORY 5 /15/88: DEALLOCATE: ( -- ) ' >BODY DUP @ SWAP OFF ?DUP IF deallocate ABORT" Memory deallocation error" THEN ; 5 /15/88 5 /15/88Name this file Set CAPS to off and restore when done only need 64K for kernel 5 /15/88FOR.ME allocate the requested # of paragraphs for the current program allocate.memory ( n -- a/e f ) Allocate the requested n paragraphs of memory. Return a true and an address or a false and an error code. deallocate ( seg -- e False or True ) pass a segment of memory to release, return a true or return a false and an error code. 5 /15/88 see Screen 0 for usage of ALLOCATE: [ALLOCATE:] is a version of ALLOCATE: to be used inside a definition to reserve the next word in the compilation stream
