in portable/ARMv8M/non_secure/portable/GCC/ARM_CM33/portasm.c [212:378]
void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" .extern SecureContext_SaveContext \n"
" .extern SecureContext_LoadContext \n"
" \n"
" ldr r3, xSecureContextConst \n"/* Read the location of xSecureContext i.e. &( xSecureContext ). */
" ldr r0, [r3] \n"/* Read xSecureContext - Value of xSecureContext must be in r0 as it is used as a parameter later. */
" ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r3] \n"/* Read pxCurrentTCB - Value of pxCurrentTCB must be in r1 as it is used as a parameter later. */
" mrs r2, psp \n"/* Read PSP in r2. */
" \n"
" cbz r0, save_ns_context \n"/* No secure context to save. */
" push {r0-r2, r14} \n"
" bl SecureContext_SaveContext \n"/* Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */
" pop {r0-r3} \n"/* LR is now in r3. */
" mov lr, r3 \n"/* LR = r3. */
" lsls r1, r3, #25 \n"/* r1 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
" bpl save_ns_context \n"/* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
" \n"
" ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r3] \n"/* Read pxCurrentTCB.*/
#if ( configENABLE_MPU == 1 )
" subs r2, r2, #16 \n"/* Make space for xSecureContext, PSPLIM, CONTROL and LR on the stack. */
" str r2, [r1] \n"/* Save the new top of stack in TCB. */
" mrs r1, psplim \n"/* r1 = PSPLIM. */
" mrs r3, control \n"/* r3 = CONTROL. */
" mov r4, lr \n"/* r4 = LR/EXC_RETURN. */
" stmia r2!, {r0, r1, r3, r4} \n"/* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */
#else /* configENABLE_MPU */
" subs r2, r2, #12 \n"/* Make space for xSecureContext, PSPLIM and LR on the stack. */
" str r2, [r1] \n"/* Save the new top of stack in TCB. */
" mrs r1, psplim \n"/* r1 = PSPLIM. */
" mov r3, lr \n"/* r3 = LR/EXC_RETURN. */
" stmia r2!, {r0, r1, r3} \n"/* Store xSecureContext, PSPLIM and LR on the stack. */
#endif /* configENABLE_MPU */
" b select_next_task \n"
" \n"
" save_ns_context: \n"
" ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r3] \n"/* Read pxCurrentTCB. */
#if ( configENABLE_FPU == 1 )
" tst lr, #0x10 \n"/* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the FPU is in use. */
" it eq \n"
" vstmdbeq r2!, {s16-s31} \n"/* Store the FPU registers which are not saved automatically. */
#endif /* configENABLE_FPU */
#if ( configENABLE_MPU == 1 )
" subs r2, r2, #48 \n"/* Make space for xSecureContext, PSPLIM, CONTROL, LR and the remaining registers on the stack. */
" str r2, [r1] \n"/* Save the new top of stack in TCB. */
" adds r2, r2, #16 \n"/* r2 = r2 + 16. */
" stm r2, {r4-r11} \n"/* Store the registers that are not saved automatically. */
" mrs r1, psplim \n"/* r1 = PSPLIM. */
" mrs r3, control \n"/* r3 = CONTROL. */
" mov r4, lr \n"/* r4 = LR/EXC_RETURN. */
" subs r2, r2, #16 \n"/* r2 = r2 - 16. */
" stmia r2!, {r0, r1, r3, r4} \n"/* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */
#else /* configENABLE_MPU */
" subs r2, r2, #44 \n"/* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
" str r2, [r1] \n"/* Save the new top of stack in TCB. */
" adds r2, r2, #12 \n"/* r2 = r2 + 12. */
" stm r2, {r4-r11} \n"/* Store the registers that are not saved automatically. */
" mrs r1, psplim \n"/* r1 = PSPLIM. */
" mov r3, lr \n"/* r3 = LR/EXC_RETURN. */
" subs r2, r2, #12 \n"/* r2 = r2 - 12. */
" stmia r2!, {r0, r1, r3} \n"/* Store xSecureContext, PSPLIM and LR on the stack. */
#endif /* configENABLE_MPU */
" \n"
" select_next_task: \n"
" mov r0, %0 \n"/* r0 = configMAX_SYSCALL_INTERRUPT_PRIORITY */
" msr basepri, r0 \n"/* Disable interrupts upto configMAX_SYSCALL_INTERRUPT_PRIORITY. */
" dsb \n"
" isb \n"
" bl vTaskSwitchContext \n"
" mov r0, #0 \n"/* r0 = 0. */
" msr basepri, r0 \n"/* Enable interrupts. */
" \n"
" ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r3] \n"/* Read pxCurrentTCB. */
" ldr r2, [r1] \n"/* The first item in pxCurrentTCB is the task top of stack. r2 now points to the top of stack. */
" \n"
#if ( configENABLE_MPU == 1 )
" dmb \n"/* Complete outstanding transfers before disabling MPU. */
" ldr r3, xMPUCTRLConst \n"/* r3 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r4, [r3] \n"/* Read the value of MPU_CTRL. */
" bic r4, #1 \n"/* r4 = r4 & ~1 i.e. Clear the bit 0 in r4. */
" str r4, [r3] \n"/* Disable MPU. */
" \n"
" adds r1, #4 \n"/* r1 = r1 + 4. r1 now points to MAIR0 in TCB. */
" ldr r4, [r1] \n"/* r4 = *r1 i.e. r4 = MAIR0. */
" ldr r3, xMAIR0Const \n"/* r3 = 0xe000edc0 [Location of MAIR0]. */
" str r4, [r3] \n"/* Program MAIR0. */
" ldr r3, xRNRConst \n"/* r3 = 0xe000ed98 [Location of RNR]. */
" movs r4, #4 \n"/* r4 = 4. */
" str r4, [r3] \n"/* Program RNR = 4. */
" adds r1, #4 \n"/* r1 = r1 + 4. r1 now points to first RBAR in TCB. */
" ldr r3, xRBARConst \n"/* r3 = 0xe000ed9c [Location of RBAR]. */
" ldmia r1!, {r4-r11} \n"/* Read 4 sets of RBAR/RLAR registers from TCB. */
" stmia r3!, {r4-r11} \n"/* Write 4 set of RBAR/RLAR registers using alias registers. */
" \n"
" ldr r3, xMPUCTRLConst \n"/* r3 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r4, [r3] \n"/* Read the value of MPU_CTRL. */
" orr r4, #1 \n"/* r4 = r4 | 1 i.e. Set the bit 0 in r4. */
" str r4, [r3] \n"/* Enable MPU. */
" dsb \n"/* Force memory writes before continuing. */
#endif /* configENABLE_MPU */
" \n"
#if ( configENABLE_MPU == 1 )
" ldmia r2!, {r0, r1, r3, r4} \n"/* Read from stack - r0 = xSecureContext, r1 = PSPLIM, r3 = CONTROL and r4 = LR. */
" msr psplim, r1 \n"/* Restore the PSPLIM register value for the task. */
" msr control, r3 \n"/* Restore the CONTROL register value for the task. */
" mov lr, r4 \n"/* LR = r4. */
" ldr r3, xSecureContextConst \n"/* Read the location of xSecureContext i.e. &( xSecureContext ). */
" str r0, [r3] \n"/* Restore the task's xSecureContext. */
" cbz r0, restore_ns_context \n"/* If there is no secure context for the task, restore the non-secure context. */
" ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r3] \n"/* Read pxCurrentTCB. */
" push {r2, r4} \n"
" bl SecureContext_LoadContext \n"/* Restore the secure context. Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */
" pop {r2, r4} \n"
" mov lr, r4 \n"/* LR = r4. */
" lsls r1, r4, #25 \n"/* r1 = r4 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
" bpl restore_ns_context \n"/* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
" msr psp, r2 \n"/* Remember the new top of stack for the task. */
" bx lr \n"
#else /* configENABLE_MPU */
" ldmia r2!, {r0, r1, r4} \n"/* Read from stack - r0 = xSecureContext, r1 = PSPLIM and r4 = LR. */
" msr psplim, r1 \n"/* Restore the PSPLIM register value for the task. */
" mov lr, r4 \n"/* LR = r4. */
" ldr r3, xSecureContextConst \n"/* Read the location of xSecureContext i.e. &( xSecureContext ). */
" str r0, [r3] \n"/* Restore the task's xSecureContext. */
" cbz r0, restore_ns_context \n"/* If there is no secure context for the task, restore the non-secure context. */
" ldr r3, pxCurrentTCBConst \n"/* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r3] \n"/* Read pxCurrentTCB. */
" push {r2, r4} \n"
" bl SecureContext_LoadContext \n"/* Restore the secure context. Params are in r0 and r1. r0 = xSecureContext and r1 = pxCurrentTCB. */
" pop {r2, r4} \n"
" mov lr, r4 \n"/* LR = r4. */
" lsls r1, r4, #25 \n"/* r1 = r4 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
" bpl restore_ns_context \n"/* bpl - branch if positive or zero. If r1 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
" msr psp, r2 \n"/* Remember the new top of stack for the task. */
" bx lr \n"
#endif /* configENABLE_MPU */
" \n"
" restore_ns_context: \n"
" ldmia r2!, {r4-r11} \n"/* Restore the registers that are not automatically restored. */
#if ( configENABLE_FPU == 1 )
" tst lr, #0x10 \n"/* Test Bit[4] in LR. Bit[4] of EXC_RETURN is 0 if the FPU is in use. */
" it eq \n"
" vldmiaeq r2!, {s16-s31} \n"/* Restore the FPU registers which are not restored automatically. */
#endif /* configENABLE_FPU */
" msr psp, r2 \n"/* Remember the new top of stack for the task. */
" bx lr \n"
" \n"
" .align 4 \n"
"pxCurrentTCBConst: .word pxCurrentTCB \n"
"xSecureContextConst: .word xSecureContext \n"
#if ( configENABLE_MPU == 1 )
"xMPUCTRLConst: .word 0xe000ed94 \n"
"xMAIR0Const: .word 0xe000edc0 \n"
"xRNRConst: .word 0xe000ed98 \n"
"xRBARConst: .word 0xe000ed9c \n"
#endif /* configENABLE_MPU */
::"i" ( configMAX_SYSCALL_INTERRUPT_PRIORITY )
);
}