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/* Project: OSLib* Description: The OS Construction Kit* Date: 1.6.2000* Idea by: Luca Abeni & Gerardo Lamastra** OSLib is an SO project aimed at developing a common, easy-to-use* low-level infrastructure for developing OS kernels and Embedded* Applications; it partially derives from the HARTIK project but it* currently is independently developed.** OSLib is distributed under GPL License, and some of its code has* been derived from the Linux kernel source; also some important* ideas come from studying the DJGPP go32 extender.** We acknowledge the Linux Community, Free Software Foundation,* D.J. Delorie and all the other developers who believe in the* freedom of software and ideas.** For legalese, check out the included GPL license.*//* Exc/IRQ handlers (asm part) *//* TODO: Unify the Exc/Int Mechanism... */#include <ll/i386/sel.h>#include <ll/i386/linkage.h>#include <ll/i386/int.h>#include <ll/i386/defs.h>.extern SYMBOL_NAME(GDT_base).dataASMFILE(Exc).globl SYMBOL_NAME(ll_irq_table).globl SYMBOL_NAME(ll_exc_table)SYMBOL_NAME_LABEL(ll_irq_table) .space 64, 0SYMBOL_NAME_LABEL(ll_exc_table) .space 64, 65.text.extern SYMBOL_NAME(ll_exc_hook).extern SYMBOL_NAME(ll_FPU_hook).globl SYMBOL_NAME(h13_bis).globl SYMBOL_NAME(exc7)/* These are the hardware handlers; they all jump to ll_handler setting *//* the interrupt number into EAX & save the registers on stack */INT(1)INT(2)INT(3)INT(4)INT(5)INT(6)INT(7)INT(8)INT(9)INT(10)INT(11)INT(12)INT(13)INT(14)INT(15)#if 0/* MPF... If we have an external FPU, it will generate* INT 13 instead of EXC 16...* We must remap it to EXC 16...*/#if 1SYMBOL_NAME_LABEL(h13_bis)/* Send EOI for 8086 coprocessor trick *//* Send 0H on Coprocessor port 0F0H */pushl %eaxxorb %al, %aloutb %al, $0x0F0movb $0x020, %aloutb %al, $0x0A0outb %al, $0x020popl %eaxmovl $16, %eaxjmp ll_handler2#elseSYMBOL_NAME_LABEL(h13_bis) pushal/* Send EOI for 8086 coprocessor trick *//* Send 0H on Coprocessor port 0F0H */xorb %al,%aloutb %al,$0x0F0movb $0x020,%aloutb %al,$0x0A0outb %al,$0x020pushl %dspushl %sspushl %espushl %fspushl %gsmovw $(X_FLATDATA_SEL),%axmovw %ax,%esmovw %ax,%dsmovl $(MATH_EXC),%eaxpushl %eax/* LL_ABORT OR EXC_HOOK?? *//*THIS SURELY WRONG!!!! FIX IT!!!! Gerardo, help me!!! */hlt/* call SYMBOL_NAME(ll_abort) */addl $4,%esppopl %gspopl %fspopl %espopl %sspopl %dspopalret#endif#endif/* The ll_handler process the request using the kernel function act_int() *//* Then sends EOI & schedules any eventual new task! */ll_handler:/* We do not know what is the DS value *//* Then we save it & set it correctly */pushl %dspushl %sspushl %espushl %fspushl %gs/* But we first transfer to the _act_int *//* the interrupt number which is required *//* as second argument */pushl %eaxmovw $(X_FLATDATA_SEL),%axmovw %ax,%esmov %ax,%ds/* Now save the actual context on stack *//* to pass it to _act_int (C caling convention) *//* CLD is necessary when calling a C function */cld/* The following could be optimized a little... */popl %eaxxorl %ebx, %ebxmovw %ss, %bx/* We must switch to a ``safe stack'' */#if 0/** OK, this is the idea: in %esp we have the address of the* stack pointer in the APPLICATION address space...* We assume that address spaces are implemented through segments...* What we have to do is to add the segment base to %esp:* - Load the GDT base in a register* - Add DS * 8 to that value* - Read the corresponding GDT entry (the segment descriptor)* - Compute the base...* It is (*p & 0xFC) | (*(p +1) & 0x0F) << 16) | *(p + 2)*/movl SYMBOL_NAME(GDT_base), %ediaddl %ebx, %edixorl %ebx, %ebxmovb 7(%edi), %bhmovb 4(%edi), %blshl $16, %ebxmovw 2(%edi), %bx/* Is it correct? I think so... Test it!!! */addl %ebx, %esp/* Save EBX for returning to our stack... */movw %ss, %dxmovw %ds, %bxmovw %bx, %sspushl %ebxpushl %edx#endifpushl %eaxmovl SYMBOL_NAME(ll_irq_table)(, %eax, 4), %ebxcall *%ebxpopl %ebx /* Store in EBX the Int number */#if 0popl %eaxpopl %ecx /* We must subtract it from ESP...*/subl %ecx, %espmovw %ax, %ss#endif/* Send EOI to master & slave (if necessary) PIC */movb $0x20,%alcmpl $0x08,%ebxjb eoi_mastereoi_slave: movl $0xA0,%edxoutb %al,%dxeoi_master: movl $0x20,%edxoutb %al,%dx/* Resume the return value of _act_int *//* & do the context switch if necessary! */#ifdef __VIRCSW__movw SYMBOL_NAME(currCtx), %axcmpw JmpSel,%axje NoPreempt3movw %ax,JmpSelljmp JmpZone#endifNoPreempt3: popl %gspopl %fspopl %espopl %sspopl %dspopaliretEXC(0)EXC(1)EXC(2)EXC(3)EXC(4)EXC(5)EXC(6)EXC(8)EXC(9)EXC(10)EXC(11)EXC(12)EXC(13)EXC(14)EXC(15)EXC(16)/* OK, this is Exception 7, and it is generated when an ESC or WAIT* intruction is reached, and the MP and TS bits are set... Basically,* it means that the FPU context must be switched*/SYMBOL_NAME_LABEL(exc7) pushalpushl %dspushl %sspushl %espushl %fspushl %gsmovw $(X_FLATDATA_SEL),%axmovw %ax,%esmovw %ax,%dscldcall SYMBOL_NAME(ll_FPU_hook)popl %gspopl %fspopl %espopl %sspopl %dspopaliretll_handler2:pushl %eaxmovw $(X_FLATDATA_SEL),%axmovw %ax,%dsmovw %ax,%es/* Again, the following could be optimized... *//*If the Exception raised in a different address space, we have toaccess the task stack from the kernel address space (the linear one...)*/popl %eaxmovw %ss, %bx/* We must switch to a ``safe stack'' */movl SYMBOL_NAME(GDT_base), %ediaddl %ebx, %edixorl %ebx, %ebxmovb 7(%edi), %bhmovb 4(%edi), %blshl $16, %ebxmovw 2(%edi), %bx/* Is it correct? I think so... Test it!!! */addl %ebx, %esp/* Save EBX for returning to our stack... */movw %ss, %dxmovw %ds, %bxmovw %bx, %sspushl %ebxpushl %edxpushl %eaxcall *SYMBOL_NAME(ll_exc_table)(, %eax, 4)addl $4,%esp/* Restore the stack pointer!!! */popl %eaxpopl %ebxmovw %ax, %sssubl %ebx, %espiret