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OS/2 Shareware BBS: 10 Tools
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10-Tools.zip
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devddemo.zip
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LDTMEM.C
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1991-01-31
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5KB
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94 lines
/*****************************************************************************/
/* Routines for managing LDT accessed memory */
/* */
/* char *phys_to_ldt(loc,count) */
/* long loc; */
/* unsigned count; */
/* */
/* Creates a selector in the current LDT from the physical address (loc) and */
/* the size of the block. Returns the selector as the function value. If */
/* The creation fails, the return pointer is 0000:0000. */
/* */
/* ------------------------------------------------------------------------- */
/* */
/* int free_virt(selector) */
/* unsigned selector; */
/* */
/* Gives the LDT selector back to OS/2 for later use. Returns 0 if */
/* successful, -1 if the return was rejected by OS/2. */
/* */
/*****************************************************************************/
#include "demo.h"
int far free_virt(selctr)
unsigned selctr;
{
union cpu_regs in_regs,out_regs;
union cpu_regs *ptr;
ptr = &in_regs; /* Make sure ES = DS */
ptr->W.AX = selctr;
in_regs.W.AX = selctr; /* AX = Segment to give back */
in_regs.B.DH = 2; /* Say we are giving it back */
in_regs.B.DL = devhlp_PhysToUVirt; /* DevHlp command */
in_regs.W.es_valid = FALSE; /* Use current ES and DS regs */
in_regs.W.ds_valid = FALSE;
dev_help(&in_regs,&out_regs);
/* If failure */
if ((out_regs.W.flags & 0x0001) != 0) { /* Return -1 */
return(-1);
} /* Else */
return(0); /* Return 0 */
}
_32bits far phys_to_ldt1(loc,count)
_32bits loc;
unsigned count;
{
union cpu_regs in_regs,out_regs;
_32bits temp;
in_regs.W.AX = loc._2words.high; /* AX:BX points to phys address */
in_regs.W.BX = loc._2words.low; /* AX:BX points to phys address */
in_regs.W.CX = count; /* CX has the size */
in_regs.B.DH = 1; /* Allocate above the 1M line */
in_regs.B.DL = devhlp_PhysToUVirt;
in_regs.W.es_valid = FALSE; /* struct ES not valid */
in_regs.W.ds_valid = FALSE; /* struct DS not valid */
dev_help1(&in_regs,&out_regs); /* Call DevHlp1 */
if ((out_regs.W.flags & 0x0001) != 0) { /* If failure */
temp.phys = 0;
return(temp); /* Return 0000:0000 */
}
temp._2words.high = out_regs.W.ES; /* Else, return pointer */
temp._2words.low = out_regs.W.BX;
return(temp);
}
_32bits far phys_to_ldt(loc,count)
_32bits loc;
unsigned count;
{
union cpu_regs in_regs,out_regs;
_32bits temp;
in_regs.W.AX = loc._2words.high; /* AX:BX points to phys address */
in_regs.W.BX = loc._2words.low; /* AX:BX points to phys address */
in_regs.W.CX = count; /* CX has the size */
in_regs.B.DH = 1; /* Allocate above the 1M line */
in_regs.B.DL = devhlp_PhysToUVirt;
in_regs.W.es_valid = FALSE; /* ES not valid */
in_regs.W.ds_valid = FALSE; /* DS not valid */
dev_help(&in_regs,&out_regs); /* Call DevHlp */
if ((out_regs.W.flags & 0x0001) != 0) { /* If failure */
temp.phys = 0;
return(temp); /* Return 0000:0000 */
}
temp._2words.high = out_regs.W.ES; /* Else, return pointer */
temp._2words.low = out_regs.W.BX;
return(temp);
}