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Table of Contents
Note: This API call is for DOS and Win16 personality only. Use Family API for portability.
Int 21H, AH=48H
Version
2 and higher
Brief
ALLOCATE MEMORYY
Family API
Input
AH = 48h BX = number of paragraphs to allocate
Return
CF clear if successful
AX = segment of allocated block
CF set on error
AX = error code (07h,08h) (see #01680 at AH=59h/BX=0000h)
BX = size of largest available block
Notes
DOS 2.1-6.0 coalesces free blocks while scanning for a block to allocate
.COM programs are initially allocated the largest available memory block, and should free some memory with AH=49h before attempting any allocations
under the FlashTek X-32 DOS extender, EBX contains a protected-mode near pointer to the allocated block on a successful return
See also
AH=49h,AH=4Ah,AH=58h,AH=83h
Note
Text based on Ralf Brown Interrupt List Release 61
| osFree Macro Library | |
|---|---|
| Video I/O | @SetMode @SetCurSz @SetCurPos @GetCur @SetPage @ScrollUp @ScrollDn @Scroll @GetChAtr @PutChAtr @PutCh @SetPalet @SetColor @SetDot @GetDot @WrtTTY @VideoState @GetMode @GetDisplay @GetVideoState @GetEGAInfo @Cls |
| Hardware info | @Equipment @MemSize |
| Serial I/O | @AuxInit @AuxSendChar @AuxRecieveChar @AuxStatus |
| Tape I/O | @TapeOn @TapeOff @TapeRead @TapeWrite |
| Keyboard I/O | @KbdStatus @CharIn @CharPeek |
| Printer I/O | @PrnPrint @PrnInit @PrnStatus |
| Disk I/O | @DskReset @DskStatus @DskRead @DskWrite @DskVerify @DskFormat |
| Date and Time | @SetTime @GetTime |
| Mouse | @MouInit @MouShowPointer @MouStatus @MouSetPos @MouSetMickey @MouRegion |
| Memory manager | @ModBlok SET_BLOCK |