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

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This commit is contained in:
Joel Sherrill
1998-03-25 18:46:47 +00:00
parent 059dbcf5f5
commit c80add4623
6 changed files with 40 additions and 40 deletions
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4
c/src/exec/score/cpu/m68k/cpu.c
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@@ -147,10 +147,6 @@ void _CPU_Install_interrupt_stack( void )
void *isp = _CPU_Interrupt_stack_high;
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
}

15
c/src/exec/score/cpu/m68k/cpu.h
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@@ -34,19 +34,16 @@ extern "C" {
/*
* 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
/*

49
c/src/exec/score/cpu/m68k/cpu_asm.s
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@@ -108,9 +108,8 @@ norst: frestore a0@+ | restore the fp state frame
* transfer control to the interrupt dispatcher.
*/
/* 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
* increamented and the higher priority interrupt
@@ -119,9 +118,6 @@ norst: frestore a0@+ | restore the fp state frame
* higher priority interrupt in the new context if
* 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.
*/
#if ( M68K_HAS_VBR == 1)
@@ -141,22 +137,26 @@ norst: frestore a0@+ | restore the fp state frame
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 )
movel @( SYM (_ISR_Vector_table),d0:w:1),a0| fetch the ISR
#else
@@ -170,7 +170,18 @@ SYM (_ISR_Handler):
jbsr a0@ | invoke the user ISR
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
bne exit | If dispatch disabled, exit

4
c/src/lib/libbsp/m68k/gen68360/start/start360.s
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@@ -327,8 +327,8 @@ start:
*/
#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
/*

4
c/src/lib/libbsp/m68k/gen68360/start360/start360.s
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@@ -327,8 +327,8 @@ start:
*/
#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
/*

4
cpukit/score/cpu/m68k/cpu.c
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@@ -147,10 +147,6 @@ void _CPU_Install_interrupt_stack( void )
void *isp = _CPU_Interrupt_stack_high;
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
}