Changeset 8b2ee37c in rtems for c/src/lib/libbsp/i386/shared/irq/irq_asm.s

Timestamp:

08/19/98 20:09:59 (25 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

26b5c77f

Parents:

7549e14

Message:

Patch from Eric Valette <valette@…>:

• Use the "hlt" instruction for the Idle thread,
• Optimise interrupt PATH leadding to thread wakeup,
• Preparation for Intel exception management that should come before the end of the week...

File:

• c/src/lib/libbsp/i386/shared/irq/irq_asm.s (modified) (5 diffs)

c/src/lib/libbsp/i386/shared/irq/irq_asm.s

@@ -15 +15 @@
 #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): 
+SYM (_ISR_Handler):     
        /*
         *  Before this was point is reached the vectors unique
         *  entry point did the following:
         *
-        *     1. saved sctach registers registers eax edx ecx"
+        *     1. saved scratch registers registers eax edx ecx"
         *     2. put the vector number in ecx.
         *
@@ -177 +141 @@
         cmpl      $0, SYM (_Context_Switch_necessary)
                                             # Is task switch necessary?
-        jne       bframe                    # Yes, then build stack
+        jne       .schedule                 # Yes, then call the scheduler
 
         cmpl      $0, SYM (_ISR_Signals_to_thread_executing)
@@ -184 +148 @@
         je        .exit                     # No, exit
 
-bframe:
+        
+.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
-
+         * This code is the less critical path. In order to have a single
+         * Thread Context, we take the same frame than the one pushed on 
+         * exceptions. This makes sense because Signal is a software 
+         * exception.
+         */
+        popl    edx
+        popl    ecx
+        popl    eax
+
+        pushl   $0      # fake fault code
+        pushl   $0      # fake exception number
+
+        pusha
+        pushl   esp
+        call    _ThreadProcessSignalsFromIrq
+        addl    $4, esp
+        popa
+        addl    $8, esp
+        iret
+                        
+.schedule:
+        /*
+         * the scratch registers have already been saved and we are already
+         * back on the thread system stack. So we can call _Thread_Displatch 
+         * directly
+         */
+        call _Thread_Dispatch
+        /*
+         * fall through exit to restore complete contex (scratch registers
+         * eip, CS, Flags).
+         */
 .exit:
        /*
@@ -218 +201 @@
         popl    eax
         iret
-                
+
+                                
 #define DISTINCT_INTERRUPT_ENTRY(_vector) \
         .p2align 4                         ; \
@@ -227 +211 @@
         pushl   edx             ; \
         movl    $ _vector, ecx  ; \
-        jmp   SYM (_New_ISR_Handler) ;
+        jmp   SYM (_ISR_Handler) ;
 
 DISTINCT_INTERRUPT_ENTRY(0)