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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | pj | 1 | /* Project: OSLib |
| 2 | * Description: The OS Construction Kit |
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| 3 | * Date: 1.6.2000 |
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| 4 | * Idea by: Luca Abeni & Gerardo Lamastra |
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| 5 | * |
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| 6 | * OSLib is an SO project aimed at developing a common, easy-to-use |
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| 7 | * low-level infrastructure for developing OS kernels and Embedded |
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| 8 | * Applications; it partially derives from the HARTIK project but it |
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| 9 | * currently is independently developed. |
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| 10 | * |
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| 11 | * OSLib is distributed under GPL License, and some of its code has |
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| 12 | * been derived from the Linux kernel source; also some important |
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| 13 | * ideas come from studying the DJGPP go32 extender. |
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| 14 | * |
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| 15 | * We acknowledge the Linux Community, Free Software Foundation, |
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| 16 | * D.J. Delorie and all the other developers who believe in the |
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| 17 | * freedom of software and ideas. |
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| 18 | * |
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| 19 | * For legalese, check out the included GPL license. |
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| 20 | */ |
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| 21 | |||
| 22 | /* Context switch code */ |
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| 23 | |||
| 24 | #include <ll/i386/sel.h> |
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| 25 | #include <ll/i386/linkage.h> |
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| 26 | #include <ll/i386/defs.h> |
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| 27 | |||
| 28 | .data |
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| 29 | |||
| 30 | ASMFILE(Context) |
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| 31 | |||
| 32 | .globl SYMBOL_NAME(currCtx) |
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| 33 | .globl JmpSel |
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| 34 | .globl JmpZone |
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| 35 | |||
| 36 | SYMBOL_NAME_LABEL(currCtx) .word 0 |
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| 37 | |||
| 38 | JmpZone: |
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| 39 | JmpOffset: |
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| 40 | .word 0 |
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| 41 | .word 0 |
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| 42 | JmpSel: |
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| 43 | .word 0 |
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| 44 | |||
| 45 | .text |
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| 46 | |||
| 47 | .globl SYMBOL_NAME(context_save) |
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| 48 | .globl SYMBOL_NAME(context_change) |
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| 49 | .globl SYMBOL_NAME(context_load) |
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| 50 | .globl SYMBOL_NAME(init_TR) |
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| 51 | |||
| 52 | /* This function assign a value to the TASK register of 386 architecture */ |
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| 53 | /* We MUST do this BEFORE we use the HW multitask */ |
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| 54 | |||
| 55 | SYMBOL_NAME_LABEL(init_TR) |
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| 56 | pushl %ebp |
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| 57 | movl %esp,%ebp |
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| 58 | movl 8(%ebp),%eax |
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| 59 | ltrw %ax |
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| 60 | movw %ax,JmpSel |
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| 61 | movw %ax,SYMBOL_NAME(currCtx) |
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| 62 | popl %ebp |
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| 63 | ret |
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| 64 | |||
| 65 | /* CONTEXT __cdecl context_save(void); */ |
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| 66 | /* The context is returned into AX; Interrupts are also cleared as we are */ |
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| 67 | /* entering into kernel primitives */ |
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| 68 | |||
| 69 | SYMBOL_NAME_LABEL(context_save) |
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| 70 | xorl %eax,%eax |
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| 71 | strw %ax |
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| 72 | ret |
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| 73 | |||
| 74 | /* void __cdecl context_change(CONTEXT c) */ |
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| 75 | /* Use 386 task switch ability. This is the last call of any preemption */ |
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| 76 | /* generating primitive; when the original task is re-activated the */ |
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| 77 | /* interrupt flag is restored with STI */ |
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| 78 | /* In 32 bit systems, context_load is an alias for context_change!*/ |
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| 79 | |||
| 80 | SYMBOL_NAME_LABEL(context_load) |
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| 81 | SYMBOL_NAME_LABEL(context_change) |
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| 82 | pushl %ebp |
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| 83 | movl %esp,%ebp |
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| 84 | movw $(X_FLATDATA_SEL),%ax |
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| 85 | movw %ax,%ds |
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| 86 | movw %ax,%es |
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| 87 | movl 8(%ebp),%eax |
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| 88 | cmpw JmpSel,%ax |
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| 89 | je NoPreempt |
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| 90 | movw %ax,JmpSel |
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| 322 | giacomo | 91 | ljmp *JmpZone |
| 2 | pj | 92 | NoPreempt: popl %ebp |
| 93 | ret |
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| 94 |