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/*
* FreeRTOS Kernel V10.3.0
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
#include "FreeRTOSConfig.h"
#define portCONTEXT_SIZE 160
#define portEPC_STACK_LOCATION 152
#define portSTATUS_STACK_LOCATION 156
#define portFPCSR_STACK_LOCATION 0
#define portTASK_HAS_FPU_STACK_LOCATION 0
#define portFPU_CONTEXT_SIZE 264
/******************************************************************/
.macro portSAVE_FPU_REGS offset, base
/* Macro to assist with saving just the FPU registers to the
* specified address and base offset,
* offset is a constant, base is the base pointer register */
sdc1 $f31, \offset + 248(\base)
sdc1 $f30, \offset + 240(\base)
sdc1 $f29, \offset + 232(\base)
sdc1 $f28, \offset + 224(\base)
sdc1 $f27, \offset + 216(\base)
sdc1 $f26, \offset + 208(\base)
sdc1 $f25, \offset + 200(\base)
sdc1 $f24, \offset + 192(\base)
sdc1 $f23, \offset + 184(\base)
sdc1 $f22, \offset + 176(\base)
sdc1 $f21, \offset + 168(\base)
sdc1 $f20, \offset + 160(\base)
sdc1 $f19, \offset + 152(\base)
sdc1 $f18, \offset + 144(\base)
sdc1 $f17, \offset + 136(\base)
sdc1 $f16, \offset + 128(\base)
sdc1 $f15, \offset + 120(\base)
sdc1 $f14, \offset + 112(\base)
sdc1 $f13, \offset + 104(\base)
sdc1 $f12, \offset + 96(\base)
sdc1 $f11, \offset + 88(\base)
sdc1 $f10, \offset + 80(\base)
sdc1 $f9, \offset + 72(\base)
sdc1 $f8, \offset + 64(\base)
sdc1 $f7, \offset + 56(\base)
sdc1 $f6, \offset + 48(\base)
sdc1 $f5, \offset + 40(\base)
sdc1 $f4, \offset + 32(\base)
sdc1 $f3, \offset + 24(\base)
sdc1 $f2, \offset + 16(\base)
sdc1 $f1, \offset + 8(\base)
sdc1 $f0, \offset + 0(\base)
.endm
/******************************************************************/
.macro portLOAD_FPU_REGS offset, base
/* Macro to assist with loading just the FPU registers from the
* specified address and base offset, offset is a constant,
* base is the base pointer register */
ldc1 $f0, \offset + 0(\base)
ldc1 $f1, \offset + 8(\base)
ldc1 $f2, \offset + 16(\base)
ldc1 $f3, \offset + 24(\base)
ldc1 $f4, \offset + 32(\base)
ldc1 $f5, \offset + 40(\base)
ldc1 $f6, \offset + 48(\base)
ldc1 $f7, \offset + 56(\base)
ldc1 $f8, \offset + 64(\base)
ldc1 $f9, \offset + 72(\base)
ldc1 $f10, \offset + 80(\base)
ldc1 $f11, \offset + 88(\base)
ldc1 $f12, \offset + 96(\base)
ldc1 $f13, \offset + 104(\base)
ldc1 $f14, \offset + 112(\base)
ldc1 $f15, \offset + 120(\base)
ldc1 $f16, \offset + 128(\base)
ldc1 $f17, \offset + 136(\base)
ldc1 $f18, \offset + 144(\base)
ldc1 $f19, \offset + 152(\base)
ldc1 $f20, \offset + 160(\base)
ldc1 $f21, \offset + 168(\base)
ldc1 $f22, \offset + 176(\base)
ldc1 $f23, \offset + 184(\base)
ldc1 $f24, \offset + 192(\base)
ldc1 $f25, \offset + 200(\base)
ldc1 $f26, \offset + 208(\base)
ldc1 $f27, \offset + 216(\base)
ldc1 $f28, \offset + 224(\base)
ldc1 $f29, \offset + 232(\base)
ldc1 $f30, \offset + 240(\base)
ldc1 $f31, \offset + 248(\base)
.endm
/******************************************************************/
.macro portSAVE_CONTEXT
/* Make room for the context. First save the current status so it can be
manipulated, and the cause and EPC registers so their original values are
captured. */
mfc0 k0, _CP0_CAUSE
addiu sp, sp, -portCONTEXT_SIZE
#if ( __mips_hard_float == 1 ) && ( configUSE_TASK_FPU_SUPPORT == 1 )
/* Test if we are already using the system stack. Only tasks may use the
FPU so if we are already in a nested interrupt then the FPU context does
not require saving. */
la k1, uxInterruptNesting
lw k1, 0(k1)
bne k1, zero, 2f
nop
/* Test if the current task needs the FPU context saving. */
la k1, ulTaskHasFPUContext
lw k1, 0(k1)
beq k1, zero, 1f
nop
/* Adjust the stack to account for the additional FPU context.*/
addiu sp, sp, -portFPU_CONTEXT_SIZE
1:
/* Save the ulTaskHasFPUContext flag. */
sw k1, portTASK_HAS_FPU_STACK_LOCATION(sp)
2:
#endif
mfc0 k1, _CP0_STATUS
/* Also save s7, s6 and s5 so they can be used. Any nesting interrupts
should maintain the values of these registers across the ISR. */
sw s7, 48(sp)
sw s6, 44(sp)
sw s5, 40(sp)
sw k1, portSTATUS_STACK_LOCATION(sp)
/* Prepare to enable interrupts above the current priority. */
srl k0, k0, 0xa
ins k1, k0, 10, 7
srl k0, k0, 0x7 /* This copies the MSB of the IPL, but it would be an error if it was set anyway. */
ins k1, k0, 18, 1
ins k1, zero, 1, 4
/* s5 is used as the frame pointer. */
add s5, zero, sp
/* Check the nesting count value. */
la k0, uxInterruptNesting
lw s6, (k0)
/* If the nesting count is 0 then swap to the the system stack, otherwise
the system stack is already being used. */
bne s6, zero, 1f
nop
/* Swap to the system stack. */
la sp, xISRStackTop
lw sp, (sp)
/* Increment and save the nesting count. */
1: addiu s6, s6, 1
sw s6, 0(k0)
/* s6 holds the EPC value, this is saved after interrupts are re-enabled. */
mfc0 s6, _CP0_EPC
/* Re-enable interrupts. */
mtc0 k1, _CP0_STATUS
/* Save the context into the space just created. s6 is saved again
here as it now contains the EPC value. No other s registers need be
saved. */
sw ra, 120(s5)
sw s8, 116(s5)
sw t9, 112(s5)
sw t8, 108(s5)
sw t7, 104(s5)
sw t6, 100(s5)
sw t5, 96(s5)
sw t4, 92(s5)
sw t3, 88(s5)
sw t2, 84(s5)
sw t1, 80(s5)
sw t0, 76(s5)
sw a3, 72(s5)
sw a2, 68(s5)
sw a1, 64(s5)
sw a0, 60(s5)
sw v1, 56(s5)
sw v0, 52(s5)
sw s6, portEPC_STACK_LOCATION(s5)
sw $1, 16(s5)
/* Save the AC0, AC1, AC2, AC3 registers from the DSP. s6 is used as a
scratch register. */
mfhi s6, $ac1
sw s6, 128(s5)
mflo s6, $ac1
sw s6, 124(s5)
mfhi s6, $ac2
sw s6, 136(s5)
mflo s6, $ac2
sw s6, 132(s5)
mfhi s6, $ac3
sw s6, 144(s5)
mflo s6, $ac3
sw s6, 140(s5)
/* Save the DSP Control register */
rddsp s6
sw s6, 148(s5)
/* ac0 is done separately to match the MX port. */
mfhi s6, $ac0
sw s6, 12(s5)
mflo s6, $ac0
sw s6, 8(s5)
/* Save the FPU context if the nesting count was zero. */
#if ( __mips_hard_float == 1 ) && ( configUSE_TASK_FPU_SUPPORT == 1 )
la s6, uxInterruptNesting
lw s6, 0(s6)
addiu s6, s6, -1
bne s6, zero, 1f
nop
/* Test if the current task needs the FPU context saving. */
lw s6, portTASK_HAS_FPU_STACK_LOCATION(s5)
beq s6, zero, 1f
nop
/* Save the FPU registers. */
portSAVE_FPU_REGS ( portCONTEXT_SIZE + 8 ), s5
/* Save the FPU status register */
cfc1 s6, $f31
sw s6, (portCONTEXT_SIZE + portFPCSR_STACK_LOCATION)(s5)
1:
#endif
/* Update the task stack pointer value if nesting is zero. */
la s6, uxInterruptNesting
lw s6, (s6)
addiu s6, s6, -1
bne s6, zero, 1f
nop
/* Save the stack pointer. */
la s6, uxSavedTaskStackPointer
sw s5, (s6)
1:
.endm
/******************************************************************/
.macro portRESTORE_CONTEXT
/* Restore the stack pointer from the TCB. This is only done if the
nesting count is 1. */
la s6, uxInterruptNesting
lw s6, (s6)
addiu s6, s6, -1
bne s6, zero, 1f
nop
la s6, uxSavedTaskStackPointer
lw s5, (s6)
#if ( __mips_hard_float == 1 ) && ( configUSE_TASK_FPU_SUPPORT == 1 )
/* Restore the FPU context if required. */
lw s6, portTASK_HAS_FPU_STACK_LOCATION(s5)
beq s6, zero, 1f
nop
/* Restore the FPU registers. */
portLOAD_FPU_REGS ( portCONTEXT_SIZE + 8 ), s5
/* Restore the FPU status register. */
lw s6, ( portCONTEXT_SIZE + portFPCSR_STACK_LOCATION )(s5)
ctc1 s6, $f31
#endif
1:
/* Restore the context. */
lw s6, 128(s5)
mthi s6, $ac1
lw s6, 124(s5)
mtlo s6, $ac1
lw s6, 136(s5)
mthi s6, $ac2
lw s6, 132(s5)
mtlo s6, $ac2
lw s6, 144(s5)
mthi s6, $ac3
lw s6, 140(s5)
mtlo s6, $ac3
/* Restore DSPControl. */
lw s6, 148(s5)
wrdsp s6
lw s6, 8(s5)
mtlo s6, $ac0
lw s6, 12(s5)
mthi s6, $ac0
lw $1, 16(s5)
/* s6 is loaded as it was used as a scratch register and therefore saved
as part of the interrupt context. */
lw s7, 48(s5)
lw s6, 44(s5)
lw v0, 52(s5)
lw v1, 56(s5)
lw a0, 60(s5)
lw a1, 64(s5)
lw a2, 68(s5)
lw a3, 72(s5)
lw t0, 76(s5)
lw t1, 80(s5)
lw t2, 84(s5)
lw t3, 88(s5)
lw t4, 92(s5)
lw t5, 96(s5)
lw t6, 100(s5)
lw t7, 104(s5)
lw t8, 108(s5)
lw t9, 112(s5)
lw s8, 116(s5)
lw ra, 120(s5)
/* Protect access to the k registers, and others. */
di
ehb
/* Decrement the nesting count. */
la k0, uxInterruptNesting
lw k1, (k0)
addiu k1, k1, -1
sw k1, 0(k0)
#if ( __mips_hard_float == 1 ) && ( configUSE_TASK_FPU_SUPPORT == 1 )
/* If the nesting count is now zero then the FPU context may be restored. */
bne k1, zero, 1f
nop
/* Restore the value of ulTaskHasFPUContext */
la k0, ulTaskHasFPUContext
lw k1, 0(s5)
sw k1, 0(k0)
/* If the task does not have an FPU context then adjust the stack normally. */
beq k1, zero, 1f
nop
/* Restore the STATUS and EPC registers */
lw k0, portSTATUS_STACK_LOCATION(s5)
lw k1, portEPC_STACK_LOCATION(s5)
/* Leave the stack in its original state. First load sp from s5, then
restore s5 from the stack. */
add sp, zero, s5
lw s5, 40(sp)
/* Adjust the stack pointer to remove the FPU context */
addiu sp, sp, portFPU_CONTEXT_SIZE
beq zero, zero, 2f
nop
1: /* Restore the STATUS and EPC registers */
lw k0, portSTATUS_STACK_LOCATION(s5)
lw k1, portEPC_STACK_LOCATION(s5)
/* Leave the stack in its original state. First load sp from s5, then
restore s5 from the stack. */
add sp, zero, s5
lw s5, 40(sp)
2: /* Adjust the stack pointer */
addiu sp, sp, portCONTEXT_SIZE
#else
/* Restore the frame when there is no hardware FP support. */
lw k0, portSTATUS_STACK_LOCATION(s5)
lw k1, portEPC_STACK_LOCATION(s5)
/* Leave the stack in its original state. First load sp from s5, then
restore s5 from the stack. */
add sp, zero, s5
lw s5, 40(sp)
addiu sp, sp, portCONTEXT_SIZE
#endif // ( __mips_hard_float == 1 ) && ( configUSE_TASK_FPU_SUPPORT == 1 )
mtc0 k0, _CP0_STATUS
mtc0 k1, _CP0_EPC
ehb
eret
nop
.endm
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