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Some context switch fixes

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3066 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2010-10-31 17:08:05 +00:00
parent 2d698d3743
commit d3dbe55c2b
2 changed files with 36 additions and 21 deletions
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53
arch/avr/src/avr32/up_fullcontextrestore.S
View File

@ -67,43 +67,52 @@
up_fullcontextrestore:
/* Initially, r12 points to the r7 save area. Restore r0-r7. */
/* 07 06 05 04 03 02 01 00 xx xx xx xx xx xx xx xx xx */
/* ^r12 */
/* regs: 07 06 05 04 03 02 01 00 xx xx xx xx xx xx xx xx xx */
/* ^r12 */
ldm r12++, r0-r7
/* Now, r12 points to the SP (r13) save area. Recover the value of */
/* the stack pointer (r13). We will need to save some temporaries on */
/* the final stack. */
/* 07 06 05 04 03 02 01 00 SP xx xx xx xx xx xx xx xx */
/* ^r12 */
/* regs: 07 06 05 04 03 02 01 00 SP xx xx xx xx xx xx xx xx */
/* ^r12 */
ld.w sp, r12++
/* Now r12 points to the SR save area. Skip over the SR for now. */
/* 07 06 05 04 03 02 01 00 SP xx xx xx xx xx xx xx xx */
/* ^r12 */
/* regs: 07 06 05 04 03 02 01 00 SP xx xx xx xx xx xx xx xx */
/* ^r12 */
sub r12, -2*4
sub r12, -1*4
/* Get the pc, lr, and r12 (in r8, r9, and r10) and move them to the */
/* Get the pc, lr, and r12 (in r10, r9, and r8) and move them to the */
/* stack. We can now use r12 and lr as scratch registers. */
/* 07 06 05 04 03 02 01 00 SP xx PC LR 12 xx xx xx xx */
/* ^r12 */
/* regs: 07 06 05 04 03 02 01 00 SP xx PC LR 12 xx xx xx xx */
/* ^r12 */
/* stack: lr, r12, pc */
/* ^sp */
ldm r12++, r8-r10
stm --sp, r8-r10
ldm r12++, r8-r10 /* Get r10=pc, r9=lr, r8=r12 */
#if 0 /* See comments below */
stm --sp, r8-r10 /* Save r12, lr, and pc from the stack */
#else
st.w --sp, r10 /* Save R10=PC on the stack */
st.w --sp, r8 /* Save R8=r12 on the stack */
st.w --sp, r9 /* Save R9=lr on the stack */
#endif
/* Now r12 now points to the r11 save area. Restore r8-r11. */
/* 07 06 05 04 03 02 01 00 SP xx PC LR 12 11 10 09 08 */
/* ^r12 */
/* regs: 07 06 05 04 03 02 01 00 SP xx PC LR 12 11 10 09 08 */
/* ^r12 */
ldm r12++, r8-r11
/* r12 now points +4 beyond the end of the register save area. Restore */
/* SR. NOTE: This may enable interrupts! */
/* 07 06 05 04 03 02 01 00 SP SR PC LR 12 11 10 09 08 */
/* ^r12-4*8 ^r12 */
/* regs: 07 06 05 04 03 02 01 00 SP SR PC LR 12 11 10 09 08 */
/* ^r12-4*8 ^r12 */
ld.w lr, r12[-4*8]
mtsr AVR32_SR, lr
@ -111,8 +120,14 @@ up_fullcontextrestore:
/* Restore PC, LR and r12. Hmmm.. I need to study the behaviour of ldm */
/* when r12,lr, and pc on in ldm reglist16. I'm not sure that I want */
/* that behavior. */
/* stack: lr, r12, pc */
/* ^sp */
/* ldm sp++, r12, lr, pc */
ldm sp++, r12, lr
ld.w pc, sp++
#if 0
ldm sp++, r12, lr, pc /* Restore r12, lr, and pc from the stack */
#else
ld.w lr, sp++ /* Recover lr from the stack */
ld.w r12, sp++ /* Recover r12 from the stack */
ld.w pc, sp++ /* Jump to the address on the stack */
#endif
.end

4
arch/avr/src/avr32/up_initialstate.c
View File

@ -111,9 +111,9 @@ void up_initial_state(_TCB *tcb)
/* Enable or disable interrupts, based on user configuration */
# ifdef CONFIG_SUPPRESS_INTERRUPTS
xcp->regs[REG_SR] = ;
xcp->regs[REG_SR] = avr32_sr() | AVR32_SR_GM_MASK;
# else
xcp->regs[REG_SR] = 0;
xcp->regs[REG_SR] = avr32_sr() & ~AVR32_SR_GM_MASK;
# endif
}