Save a few more cycles in cpu_switch() and cpu_throw().
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6c98f40194
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@ -128,11 +128,9 @@ __FBSDID("$FreeBSD$");
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.Lcpu_do_powersave:
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.word _C_LABEL(cpu_do_powersave)
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ENTRY(cpu_throw)
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mov r4, r0
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mov r5, r1
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/*
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* r4 = oldtd
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* r5 = newtd
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*/
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@ -148,7 +146,6 @@ ENTRY(cpu_throw)
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/*
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* r0 = Pointer to L1 slot for vector_page (or NULL)
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* r1 = lwp0's DACR
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* r4 = lwp we're switching from
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* r5 = lwp0
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* r6 = exit func
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* r7 = lwp0's PCB
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@ -200,9 +197,15 @@ ENTRY(cpu_throw)
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ldr r13, [r7, #(PCB_SP)]
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#endif
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mov r0, #0x00000000 /* r5 = old lwp = NULL */
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mov r1, r5
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b .Lswitch_resume
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/* We have a new curthread now so make a note it */
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ldr r6, .Lcurthread
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str r5, [r6]
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/* Hook in a new pcb */
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ldr r6, .Lcurpcb
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str r7, [r6]
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ldmfd sp, {r4-r7, pc}
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ENTRY(cpu_switch)
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stmfd sp!, {r4-r7, lr}
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@ -228,16 +231,6 @@ ENTRY(cpu_switch)
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ldr r2, [r1, #TD_PCB]
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str r2, [r7]
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/*
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* If the old lwp on entry to cpu_switch was zero then the
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* process that called it was exiting. This means that we do
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* not need to save the current context. Instead we can jump
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* straight to restoring the context for the new process.
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*/
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teq r0, #0x00000000
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beq .Lswitch_return
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/* rem: r1 = new process */
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/* rem: interrupts are enabled */
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@ -267,16 +260,15 @@ ENTRY(cpu_switch)
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/* r1 now free! */
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/*
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* This can be optimised... We know we want to go from SVC32
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* mode to UND32 mode
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*/
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mrs r3, cpsr
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bic r2, r3, #(PSR_MODE)
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orr r2, r2, #(PSR_UND32_MODE)
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msr cpsr_c, r2
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/*
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* We can do that, since
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* PSR_SVC32_MODE|PSR_UND32_MODE == MSR_UND32_MODE
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*/
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orr r8, r3, #(PSR_UND32_MODE)
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msr cpsr_c, r8
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str sp, [r8, #(PCB_UND_SP)]
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str sp, [r2, #(PCB_UND_SP)]
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msr cpsr_c, r3 /* Restore the old mode */
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/* rem: r8 = old PCB */
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@ -378,6 +370,10 @@ ENTRY(cpu_switch)
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movne r0, #0 /* We *know* vector_page's VA is 0x0 */
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movne lr, pc
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ldrne pc, [r10, #CF_TLB_FLUSHID_SE]
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/*
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* We can do that, since
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* PSR_SVC32_MODE|PSR_UND32_MODE == MSR_UND32_MODE
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*/
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.Lcs_context_switched:
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@ -385,14 +381,13 @@ ENTRY(cpu_switch)
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/* rem: r9 = new PCB */
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/*
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* This can be optimised... We know we want to go from SVC32
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* mode to UND32 mode
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*/
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mrs r3, cpsr
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bic r2, r3, #(PSR_MODE)
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orr r2, r2, #(PSR_UND32_MODE)
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msr cpsr_c, r2
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/*
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* We can do that, since
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* PSR_SVC32_MODE|PSR_UND32_MODE == MSR_UND32_MODE
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*/
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orr r2, r3, #(PSR_UND32_MODE)
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msr cpsr_c, r2
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ldr sp, [r9, #(PCB_UND_SP)]
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