| 1,7 → 1,7 |
|---|
| /* This file is part of the SvarCOM project and is published under the terms |
| * of the MIT license. |
| * |
| * Copyright (C) 2021 Mateusz Viste |
| * Copyright (C) 2021-2022 Mateusz Viste |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| 225,3 → 225,97 |
|---|
| *comspecptr = 0; |
| } |
| } |
| |
| |
| /* allocates bytes of far memory, flags it as belonging to rmod |
| * the new block can be optionally flagged as 'ident' (if not null) |
| * returns a far ptr to the allocated block, or NULL on error */ |
| void far *rmod_fmalloc(unsigned short bytes, unsigned short rmod_seg, char *ident) { |
| unsigned short far *owner; |
| unsigned short newseg = 0; |
| |
| /* ask DOS for a memory block (as high as possible) */ |
| _asm { |
| push bx /* save initial value in BX so I can restore it later */ |
| |
| /* get current allocation strategy and save it on stack */ |
| mov ax, 0x5800 |
| int 0x21 |
| push ax |
| |
| /* set strategy to 'last fit, try high then low memory' */ |
| mov ax, 0x5801 |
| mov bx, 0x0082 |
| int 0x21 |
| |
| /* ask for a memory block and save the given segment to rmodseg */ |
| mov ah, 0x48 /* Allocate Memory */ |
| mov bx, bytes |
| add bx, 15 /* convert bytes to paragraphs */ |
| shr bx, 1 /* bx /= 16 */ |
| shr bx, 1 |
| shr bx, 1 |
| shr bx, 1 |
| int 0x21 |
| |
| /* error handling */ |
| jc FAIL |
| |
| /* save newly allocated segment to newseg */ |
| mov newseg, ax |
| |
| FAIL: |
| /* restore initial allocation strategy */ |
| mov ax, 0x5801 |
| pop bx |
| int 0x21 |
| |
| pop bx /* restore BX to its initial value */ |
| } |
| |
| if (newseg == 0) return(NULL); |
| |
| /* mark memory as "owned by rmod" */ |
| owner = (void far *)(MK_FP(newseg - 1, 1)); |
| *owner = rmod_seg; |
| |
| /* set the MCB description to ident, if provided */ |
| if (ident) { |
| char far *mcbdesc = MK_FP(newseg - 1, 8); |
| int i; |
| _fmemset(mcbdesc, 0, 8); |
| for (i = 0; (i < 8) && (ident[i] != 0); i++) { /* field's length is limited to 8 bytes max */ |
| mcbdesc[i] = ident[i]; |
| } |
| } |
| |
| return(MK_FP(newseg, 0)); |
| } |
| |
| |
| /* free memory previously allocated by rmod_ffmalloc() */ |
| void rmod_ffree(void far *ptr) { |
| unsigned short ptrseg; |
| unsigned short myseg = 0; |
| unsigned short far *owner; |
| if (ptr == NULL) return; |
| ptrseg = FP_SEG(ptr); |
| |
| /* get my own segment */ |
| _asm { |
| mov myseg, cs |
| } |
| |
| /* mark memory in MCB as my own, otherwise DOS might refuse to free it */ |
| owner = MK_FP(ptrseg - 1, 1); |
| *owner = myseg; |
| |
| /* free the memory block */ |
| _asm { |
| push es |
| mov ah, 0x49 /* Free Memory Block */ |
| mov es, ptrseg |
| int 0x21 |
| pop es |
| } |
| } |