optimized isr.asm a bit

git-svn-id: svn://anubis/hos/trunk@64 5b3e749e-e535-0410-8002-a9bb6afbdfca

kernel/boot/isr.asm

@@ -2,6 +2,7 @@
 ; C ISR routine
 [extern isr]
 
+
 ; Macro for creating a single ISR label
 ; We need to push a junk value on the stack first
 ; if the interrupt number is not 8 or 10-14.
@@ -13,49 +14,44 @@ isr_%1:
     %if ( (%1 != 8) && (%1 < 10 || %1 > 14) )
         push    eax                 ; junk value to take error code stack space
     %endif
-    push    eax
+    pusha                           ; eax, ecx, edx, ebx, esp, ebp, esi, edi
     mov     al, %1                  ; save interrupt number in al
-    jmp     isr_common
+    %if ($ - isr_common) < 127      ; do a short jump and save 3 bytes if we can
+        jmp short isr_common
+    %else
+        jmp     isr_common
+    %endif
 %endmacro
 
-; Loop to create all of our ISR labels
+
+; The common ISR routine
+isr_common:
+    push    ds
+    push    es
+    push    fs
+    push    gs
+
+    push    esp                     ; pointer to interrupt stack
+    push    eax                     ; interrupt number
+; TODO: uncomment when isr() is defined so the build won't break
+;    call    isr
+    pop     eax                     ; restore stack pointer (this is shorter
+    pop     eax                     ; than "add esp, 8" and "lea esp, [esp+8]")
+
+    pop     gs
+    pop     fs
+    pop     es
+    pop     ds
+    popa                            ; edi, esi, ebp, <null>, ebx, edx, ecx, eax
+    lea     esp, [esp+4]
+
+    iret
+
+
+; Loop to create all of our ISR entry points
 %assign i 0
 %rep 50
     isr_label i
     %assign i i+1
 %endrep
 
-; The common ISR routine
-isr_common:
-    push    ebx
-    push    ecx
-    push    edx
-    push    edi
-    push    esi
-    push    ebp
-    push    ds
-    push    es
-    push    fs
-    push    gs
-
-    push    esp
-    push    eax
-; TODO: currently commented since there is no isr()
-; so the build will not break
-;    call    isr
-    add     esp, 8
-
-    pop     gs
-    pop     fs
-    pop     es
-    pop     ds
-    pop     ebp
-    pop     esi
-    pop     edi
-    pop     edx
-    pop     ecx
-    pop     ebx
-    pop     eax                     ; error code can be ignored now
-    pop     eax
-
-    iret