diff options
Diffstat (limited to 'c/src/lib/libbsp/i386/shared/irq/irq_asm.s')
| -rw-r--r-- | c/src/lib/libbsp/i386/shared/irq/irq_asm.s | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/i386/shared/irq/irq_asm.s b/c/src/lib/libbsp/i386/shared/irq/irq_asm.s new file mode 100644 index 0000000000..7765a9dd22 --- /dev/null +++ b/c/src/lib/libbsp/i386/shared/irq/irq_asm.s @@ -0,0 +1,261 @@ +/* irq.c + * + * This file contains the implementation of the function described in irq.h + * + * CopyRight (C) 1998 valette@crf.canon.fr + * + * The license and distribution terms for this file may be + * found in found in the file LICENSE in this distribution or at + * http://www.OARcorp.com/rtems/license.html. + * + * $Id$ + */ + +#include "asm.h" +#include <irq_asm.h> + +.set SAVED_REGS , 32 # space consumed by saved regs +.set EIP_OFFSET , SAVED_REGS # offset of tasks eip +.set CS_OFFSET , EIP_OFFSET+4 # offset of tasks code segment +.set EFLAGS_OFFSET , CS_OFFSET+4 # offset of tasks eflags + + +/*PAGE + * void _new_ISR_Displatch() + * + * Entry point from the outermost interrupt service routine exit. + * The current stack is the supervisor mode stack. + */ + + PUBLIC (_new_ISR_Displatch) +SYM (_New_ISR_Displatch): + + call SYM (_Thread_Dispatch) # invoke Dispatcher + + /* + * BEGINNING OF DE-ESTABLISH SEGMENTS + * + * NOTE: Make sure there is code here if code is added to + * load the segment registers. + * + */ + + /***** DE-ESTABLISH SEGMENTS CODE GOES HERE ****/ + + /* + * END OF DE-ESTABLISH SEGMENTS + */ + + popa # restore general registers + iret # return to interrupted thread + + +SYM (_New_ISR_Handler): + /* + * Before this was point is reached the vectors unique + * entry point did the following: + * + * 1. saved sctach registers registers eax edx ecx" + * 2. put the vector number in ecx. + * + * BEGINNING OF ESTABLISH SEGMENTS + * + * WARNING: If an interrupt can occur when the segments are + * not correct, then this is where we should establish + * the segments. In addition to establishing the + * segments, it may be necessary to establish a stack + * in the current data area on the outermost interrupt. + * + * NOTE: If the previous values of the segment registers are + * pushed, do not forget to adjust SAVED_REGS. + * + * NOTE: Make sure the exit code which restores these + * when this type of code is needed. + */ + + /***** ESTABLISH SEGMENTS CODE GOES HERE ******/ + + /* + * END OF ESTABLISH SEGMENTS + */ + + /* + * Now switch stacks if necessary + */ + + movw SYM (i8259s_cache), ax # move current i8259 interrupt mask in ax + pushl eax # push it on the stack + /* + * compute the new PIC mask: + * + * <new mask> = <old mask> | irq_mask_or_tbl[<intr number aka ecx>] + */ + movw SYM (irq_mask_or_tbl) (,ecx,2), dx + orw dx, ax + /* + * Install new computed value on the i8259 and update cache + * accordingly + */ + movw ax, SYM (i8259s_cache) + outb $PIC_MASTER_IMR_IO_PORT + movb ah, al + outb $PIC_SLAVE_IMR_IO_PORT + + /* + * acknowledge the interrupt + * + */ + movb $PIC_EOI, al + cmpl $7, ecx + jbe .master + outb $PIC_SLAVE_COMMAND_IO_PORT +.master: + outb $PIC_MASTER_COMMAND_IO_PORT + +.check_stack_switch: + pushl ebp + movl esp, ebp # ebp = previous stack pointer + cmpl $0, SYM (_ISR_Nest_level) # is this the outermost interrupt? + jne nested # No, then continue + movl SYM (_CPU_Interrupt_stack_high), esp + + /* + * We want to insure that the old stack pointer is on the + * stack we will be on at the end of the ISR when we restore it. + * By saving it on every interrupt, all we have to do is pop it + * near the end of every interrupt. + */ + +nested: + incl SYM (_ISR_Nest_level) # one nest level deeper + incl SYM (_Thread_Dispatch_disable_level) # disable multitasking + /* + * re-enable interrupts at processor level as the current + * interrupt source is now masked via i8259 + */ + sti + + /* + * ECX is preloaded with the vector number but it is a scratch register + * so we must save it again. + */ + + pushl ecx # push vector number + mov SYM (current_irq) (,ecx,4),eax + # eax = Users handler + call *eax # invoke user ISR + /* + * disable interrupts_again + */ + cli + popl ecx # ecx = vector number + /* + * restore stack + */ + movl ebp, esp + popl ebp + + /* + * restore the original i8259 masks + */ + popl eax + movw ax, SYM (i8259s_cache) + outb $PIC_MASTER_IMR_IO_PORT + movb ah, al + outb $PIC_SLAVE_IMR_IO_PORT + + + decl SYM (_ISR_Nest_level) # one less ISR nest level + # If interrupts are nested, + # then dispatching is disabled + + decl SYM (_Thread_Dispatch_disable_level) + # unnest multitasking + # Is dispatch disabled + jne .exit # Yes, then exit + + cmpl $0, SYM (_Context_Switch_necessary) + # Is task switch necessary? + jne bframe # Yes, then build stack + + cmpl $0, SYM (_ISR_Signals_to_thread_executing) + # signals sent to Run_thread + # while in interrupt handler? + je .exit # No, exit + +bframe: + movl $0, SYM (_ISR_Signals_to_thread_executing) + /* + * complete code as if a pusha had been executed on entry + */ + pushl ebx + pushl esp + pushl ebp + pushl esi + pushl edi + # push the isf for Isr_dispatch + pushl EFLAGS_OFFSET(esp) # push tasks eflags + push cs # cs of Isr_dispatch + pushl $ SYM (_New_ISR_Displatch)# entry point + iret + +.exit: + /* + * BEGINNING OF DE-ESTABLISH SEGMENTS + * + * NOTE: Make sure there is code here if code is added to + * load the segment registers. + * + */ + + /******* DE-ESTABLISH SEGMENTS CODE GOES HERE ********/ + + /* + * END OF DE-ESTABLISH SEGMENTS + */ + popl edx + popl ecx + popl eax + iret + +#define DISTINCT_INTERRUPT_ENTRY(_vector) \ + .p2align 4 ; \ + PUBLIC (rtems_irq_prologue_ ## _vector ) ; \ +SYM (rtems_irq_prologue_ ## _vector ): \ + pushl eax ; \ + pushl ecx ; \ + pushl edx ; \ + movl $ _vector, ecx ; \ + jmp SYM (_New_ISR_Handler) ; + +DISTINCT_INTERRUPT_ENTRY(0) +DISTINCT_INTERRUPT_ENTRY(1) +DISTINCT_INTERRUPT_ENTRY(2) +DISTINCT_INTERRUPT_ENTRY(3) +DISTINCT_INTERRUPT_ENTRY(4) +DISTINCT_INTERRUPT_ENTRY(5) +DISTINCT_INTERRUPT_ENTRY(6) +DISTINCT_INTERRUPT_ENTRY(7) +DISTINCT_INTERRUPT_ENTRY(8) +DISTINCT_INTERRUPT_ENTRY(9) +DISTINCT_INTERRUPT_ENTRY(10) +DISTINCT_INTERRUPT_ENTRY(11) +DISTINCT_INTERRUPT_ENTRY(12) +DISTINCT_INTERRUPT_ENTRY(13) +DISTINCT_INTERRUPT_ENTRY(14) +DISTINCT_INTERRUPT_ENTRY(15) + + /* + * routine used to initialize the IDT by default + */ + +PUBLIC (default_raw_idt_handler) +PUBLIC (raw_idt_notify) + +SYM (default_raw_idt_handler): + pusha + cld + call raw_idt_notify + popa + iret + |