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/* Project:     OSLib
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 * Description: The OS Construction Kit
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 * Date:                1.6.2000
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 * Idea by:             Luca Abeni & Gerardo Lamastra
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 *
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 * OSLib is an SO project aimed at developing a common, easy-to-use
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 * low-level infrastructure for developing OS kernels and Embedded
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 * Applications; it partially derives from the HARTIK project but it
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 * currently is independently developed.
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 *
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 * OSLib is distributed under GPL License, and some of its code has
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 * been derived from the Linux kernel source; also some important
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 * ideas come from studying the DJGPP go32 extender.
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 *
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 * We acknowledge the Linux Community, Free Software Foundation,
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 * D.J. Delorie and all the other developers who believe in the
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 * freedom of software and ideas.
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 *
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 * For legalese, check out the included GPL license.
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 */
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/*
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   FPU Context switch & management functions!
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   Generic 32 bit module
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*/
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#include <ll/i386/hw-data.h>
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#include <ll/i386/hw-instr.h>
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#include <ll/i386/hw-func.h>
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#include <ll/i386/mem.h>
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#include <ll/i386/tss-ctx.h>
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FILE(FPU);
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extern TSS main_tss;
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BYTE LL_FPU_savearea[FPU_CONTEXT_SIZE]; /* Global FPU scratch SaveArea */
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#ifdef __FPU_DEBUG__
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    long int ndp_called = 0,ndp_switched = 0;
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#endif
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/* FPU context management */
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static TSS *LL_has_FPU = &main_tss;
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/* As the 8086 does not have an hardware mechanism to support task      */
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/* switch, also the FPU context switch is implemented via software.     */
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/* When a preemption occurs, if the task is marked as a MATH task, the  */
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/* preemption routine will save/restore the FPU context.                */
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/* The hook is called whenever a FPU context switch is necessarty       */
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void ll_FPU_hook(void)
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{
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    CONTEXT current;
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    TSS *base;
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    current = get_TR();
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    base = (TSS *)GDT_read(current, NULL, NULL, NULL);
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    clts();
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    #ifdef __FPU_DEBUG__
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        ndp_called++;
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    #endif
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    if (LL_has_FPU == base) return;
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    #ifdef __FPU_DEBUG__
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        ndp_switched++;
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    #endif
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#if 0
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    LL_FPU_save();
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    memcpy(TSS_table[LL_has_FPU].ctx_FPU,LL_FPU_savearea,FPU_CONTEXT_SIZE);
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#else 
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    save_fpu(LL_has_FPU);
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#endif
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    LL_has_FPU = base;
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#if 1
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    memcpy(LL_FPU_savearea, base->ctx_FPU, FPU_CONTEXT_SIZE);
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    LL_FPU_restore();
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#else 
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    restore_fpu(&(TSS_table[LL_has_FPU]));
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#endif
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    return;
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}
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TSS *LL_FPU_get_task(void)
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{
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    return(LL_has_FPU);
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}