FreeDOS/kernel/dyninit.c

/*
    DYNINIT.C
    
    this serves requests from the INIT modules to
    allocate dynamic data.


kernel layout:
 00000H 000FFH 00100H PSP                PSP
 00100H 004E1H 003E2H _TEXT              CODE
 004E2H 007A7H 002C6H _IO_TEXT           CODE
 007A8H 008E5H 0013EH _IO_FIXED_DATA     CODE
 008F0H 0139FH 00AB0H _FIXED_DATA        DATA
 013A0H 019F3H 00654H _DATA              DATA
 019F4H 0240DH 00A1AH _BSS               BSS

additionally: 
                      DYN_DATA           DYN 

 
 02610H 0F40EH 0CDFFH HMA_TEXT           HMA

 FCB's, f_nodes, buffers,...
 drivers 
 
 
 0F410H 122DFH 02ED0H INIT_TEXT          INIT
 122E0H 12AA5H 007C6H ID                 ID
 12AA6H 12CBFH 0021AH IB                 IB


 purpose is to move the HMA_TEXT = resident kernel
 around, so that below it - after BSS, there is data 
 addressable near by the kernel, to hold some arrays
 like f_nodes    
 
 making f_nodes near saves ~2.150 code in HMA
    
*/    
#include "portab.h"
#include "init-mod.h"
#include "dyndata.h"

#if defined(DEBUG)
    #define DebugPrintf(x) printf x
#else
    #define DebugPrintf(x)
#endif


extern struct DynS FAR Dyn;

void far *DynAlloc(char *what, unsigned num, unsigned size)
{
    void far *now;
    unsigned total = num * size;
#ifndef DEBUG
    UNREFERENCED_PARAMETER(what);
#endif
    
    if ((ULONG)total + Dyn.Allocated > 0xffff)
    {
        printf("PANIC:Dyn %lu\n", (ULONG)total + Dyn.Allocated);
        for (;;);
    }
                
    DebugPrintf(("DYNDATA:allocating %s - %u * %u bytes, total %u, %u..%u\n",
        what, num, size, total, Dyn.Allocated,Dyn.Allocated+total));
    
    now = (void far *)&Dyn.Buffer[Dyn.Allocated];
    fmemset(now, 0, total);
    
    Dyn.Allocated += total;
    
    return now;   
}    

void DynFree(void *ptr)
{
    Dyn.Allocated = (char *)ptr - (char *)Dyn.Buffer;
}

void FAR *DynLast()
{
    DebugPrintf(("dynamic data end at %p\n",(void FAR *)(Dyn.Buffer+Dyn.Allocated)));

    return Dyn.Buffer+Dyn.Allocated;
}