Changeset c80add4 in rtems

Timestamp:

03/25/98 18:46:47 (25 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

5e0fbcc

Parents:

059dbcf

Message:

m68k software interrupt stack support from Chris Johns and Eric Norum.

Files:

• c/src/exec/score/cpu/m68k/cpu.c (modified) (1 diff)
• c/src/exec/score/cpu/m68k/cpu.h (modified) (1 diff)
• c/src/exec/score/cpu/m68k/cpu_asm.s (modified) (4 diffs)
• c/src/lib/libbsp/m68k/gen68360/start/start360.s (modified) (1 diff)
• c/src/lib/libbsp/m68k/gen68360/start360/start360.s (modified) (1 diff)
• cpukit/score/cpu/m68k/cpu.c (modified) (1 diff)

c/src/exec/score/cpu/m68k/cpu.c

@@ -148 +148 @@
 
   asm volatile ( "movec %0,%%isp" : "=r" (isp) : "0" (isp) );
-#else
-#warning "PLEASE IMPLEMENT ME... There is NO dedicated interrupt stack"
-#warning "on CPUs without a dedicated hardware interrupt stack!!!"
-#warning "INTERRUPTS RUN ON A TASK STACK!!!"
 #endif
 }

c/src/exec/score/cpu/m68k/cpu.h

@@ -35 +35 @@
  *  Use the m68k's hardware interrupt stack support and have the
  *  interrupt manager allocate the memory for it.
- *
- *  NOTE:  The definitions when M68K_HAS_SEPARATE_STACKS is 0 should
- *         change when the software interrupt stack support is implemented.
  */
 
 #if ( M68K_HAS_SEPARATE_STACKS == 1)
-#define CPU_HAS_SOFTWARE_INTERRUPT_STACK FALSE
-#define CPU_HAS_HARDWARE_INTERRUPT_STACK TRUE
-#define CPU_ALLOCATE_INTERRUPT_STACK     TRUE
+#define CPU_HAS_SOFTWARE_INTERRUPT_STACK 0
+#define CPU_HAS_HARDWARE_INTERRUPT_STACK 1
+#define CPU_ALLOCATE_INTERRUPT_STACK     1
 #else
-#define CPU_HAS_SOFTWARE_INTERRUPT_STACK FALSE
-#define CPU_HAS_HARDWARE_INTERRUPT_STACK FALSE
-#define CPU_ALLOCATE_INTERRUPT_STACK     FALSE
+#define CPU_HAS_SOFTWARE_INTERRUPT_STACK 1
+#define CPU_HAS_HARDWARE_INTERRUPT_STACK 0
+#define CPU_ALLOCATE_INTERRUPT_STACK     1
 #endif
 

c/src/exec/score/cpu/m68k/cpu_asm.s

@@ -109 +109 @@
  */
 
-/*  m68000 notes:
- *
- *  with this approach, lower interrupts (1-5 for efi68k) may
+/*
+ *  With this approach, lower priority interrupts may
  *  execute twice if a higher priority interrupt is
  *  acknowledged before _Thread_Dispatch_disable is
@@ -120 +119 @@
  *  permitted by the new interrupt level mask, and (2) when
  *  the original context regains the cpu.
- *
- *  XXX: Code for switching to a software maintained interrupt stack is
- *       not in place.
  */
  
@@ -142 +138 @@
 SYM (_ISR_Handler):
         addql   #1,SYM (_Thread_Dispatch_disable_level) | disable multitasking
-        addql   #1,SYM (_ISR_Nest_level) | one nest level deeper
         moveml  d0-d1/a0-a1,a7@-         | save d0-d1,a0-a1
-
-/*
- *  NOTE FOR CPUs WITHOUT HARDWARE INTERRUPT STACK:
- *
- *  After the interrupted codes registers have been saved, it is save
- *  to switch to the software maintained interrupt stack.
- *
- *  PLEASE, if you have a m68k without a dedicated interrupt stack,
- *          implement the stack switching code.
- */
-
         movew   a7@(SAVED+FVO_OFFSET),d0 | d0 = F/VO
         andl    #0x0fff,d0               | d0 = vector offset in vbr
+
+
+#if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == 1 )
+        movew   sr,d1                   | Save status register
+        oriw    #0x700,sr               | Disable interrupts
+        tstl    SYM (_ISR_Nest_level)   | Interrupting an interrupt handler?
+        bne     1f                      | Yes, just skip over stack switch code
+        movel   SYM(_CPU_Interrupt_stack_high),a0       | End of interrupt stack
+        movel   a7,a0@-                 | Save task stack pointer
+        movel   a0,a7                   | Switch to interrupt stack
+1:
+        addql   #1,SYM(_ISR_Nest_level) | one nest level deeper
+        movew   d1,sr                   | Restore status register
+#else
+        addql   #1,SYM (_ISR_Nest_level) | one nest level deeper
+#endif /* CPU_HAS_SOFTWARE_INTERRUPT_STACK == 1 */
 
 #if ( M68K_HAS_PREINDEXING == 1 )
@@ -171 +171 @@
         addql   #4,a7                    | remove vector number
 
-        subql   #1,SYM (_ISR_Nest_level) | one less nest level
+#if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == 1 )
+        movew   sr,d0                   | Save status register
+        oriw    #0x700,sr               | Disable interrupts
+        subql   #1,SYM(_ISR_Nest_level) | Reduce interrupt-nesting count
+        bne     1f                      | Skip if return to interrupt
+        movel   (a7),a7                 | Restore task stack pointer
+1:
+        movew   d0,sr                   | Restore status register
+#else
+        subql   #1,SYM (_ISR_Nest_level) | one less nest level
+#endif /* CPU_HAS_SOFTWARE_INTERRUPT_STACK == 1 */
+
         subql   #1,SYM (_Thread_Dispatch_disable_level)
                                          | unnest multitasking

c/src/lib/libbsp/m68k/gen68360/start/start360.s

@@ -328 +328 @@
 #if ( M68K_HAS_SEPARATE_STACKS == 1 )
         oriw    #0x3000,sr              | Switch to Master Stack Pointer
-        lea     SYM(m360)+1024-64,a7    | Load stack pointer with space
-                                        |   for the Interrupt Stack
+        lea     SYM(m360)+1024-64,a7    | Put stack in dual-port ram
+                                        | a little below the interrupt stack
 #endif
 

c/src/lib/libbsp/m68k/gen68360/start360/start360.s

@@ -328 +328 @@
 #if ( M68K_HAS_SEPARATE_STACKS == 1 )
         oriw    #0x3000,sr              | Switch to Master Stack Pointer
-        lea     SYM(m360)+1024-64,a7    | Load stack pointer with space
-                                        |   for the Interrupt Stack
+        lea     SYM(m360)+1024-64,a7    | Put stack in dual-port ram
+                                        | a little below the interrupt stack
 #endif
 

cpukit/score/cpu/m68k/cpu.c

@@ -148 +148 @@
 
   asm volatile ( "movec %0,%%isp" : "=r" (isp) : "0" (isp) );
-#else
-#warning "PLEASE IMPLEMENT ME... There is NO dedicated interrupt stack"
-#warning "on CPUs without a dedicated hardware interrupt stack!!!"
-#warning "INTERRUPTS RUN ON A TASK STACK!!!"
 #endif
 }