xref: /Kernel-v10.6.2/portable/GCC/MicroBlazeV8/portasm.S (revision ef7b253b56c9788077f5ecd6c9deb4021923d646) 
1/*
2 * FreeRTOS Kernel V10.6.2
3 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
4 *
5 * SPDX-License-Identifier: MIT
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy of
8 * this software and associated documentation files (the "Software"), to deal in
9 * the Software without restriction, including without limitation the rights to
10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
11 * the Software, and to permit persons to whom the Software is furnished to do so,
12 * subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in all
15 * copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
20 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23 *
24 * https://www.FreeRTOS.org
25 * https://github.com/FreeRTOS
26 *
27 */
28
29/* FreeRTOS includes. */
30#include "FreeRTOSConfig.h"
31
32/* Xilinx library includes. */
33#include "microblaze_exceptions_g.h"
34#include "xparameters.h"
35
36/* The context is oversized to allow functions called from the ISR to write
37back into the caller stack. */
38#if( XPAR_MICROBLAZE_USE_FPU != 0 )
39    #define portCONTEXT_SIZE 136
40    #define portMINUS_CONTEXT_SIZE -136
41#else
42    #define portCONTEXT_SIZE 132
43    #define portMINUS_CONTEXT_SIZE -132
44#endif
45
46/* Offsets from the stack pointer at which saved registers are placed. */
47#define portR31_OFFSET  4
48#define portR30_OFFSET  8
49#define portR29_OFFSET  12
50#define portR28_OFFSET  16
51#define portR27_OFFSET  20
52#define portR26_OFFSET  24
53#define portR25_OFFSET  28
54#define portR24_OFFSET  32
55#define portR23_OFFSET  36
56#define portR22_OFFSET  40
57#define portR21_OFFSET  44
58#define portR20_OFFSET  48
59#define portR19_OFFSET  52
60#define portR18_OFFSET  56
61#define portR17_OFFSET  60
62#define portR16_OFFSET  64
63#define portR15_OFFSET  68
64#define portR14_OFFSET  72
65#define portR13_OFFSET  76
66#define portR12_OFFSET  80
67#define portR11_OFFSET  84
68#define portR10_OFFSET  88
69#define portR9_OFFSET   92
70#define portR8_OFFSET   96
71#define portR7_OFFSET   100
72#define portR6_OFFSET   104
73#define portR5_OFFSET   108
74#define portR4_OFFSET   112
75#define portR3_OFFSET   116
76#define portR2_OFFSET   120
77#define portCRITICAL_NESTING_OFFSET 124
78#define portMSR_OFFSET 128
79#define portFSR_OFFSET 132
80
81    .extern pxCurrentTCB
82    .extern XIntc_DeviceInterruptHandler
83    .extern vTaskSwitchContext
84    .extern uxCriticalNesting
85    .extern pulISRStack
86    .extern ulTaskSwitchRequested
87    .extern vPortExceptionHandler
88    .extern pulStackPointerOnFunctionEntry
89
90    .global _interrupt_handler
91    .global VPortYieldASM
92    .global vPortStartFirstTask
93    .global vPortExceptionHandlerEntry
94
95
96.macro portSAVE_CONTEXT
97
98    /* Make room for the context on the stack. */
99    addik r1, r1, portMINUS_CONTEXT_SIZE
100
101    /* Stack general registers. */
102    swi r31, r1, portR31_OFFSET
103    swi r30, r1, portR30_OFFSET
104    swi r29, r1, portR29_OFFSET
105    swi r28, r1, portR28_OFFSET
106    swi r27, r1, portR27_OFFSET
107    swi r26, r1, portR26_OFFSET
108    swi r25, r1, portR25_OFFSET
109    swi r24, r1, portR24_OFFSET
110    swi r23, r1, portR23_OFFSET
111    swi r22, r1, portR22_OFFSET
112    swi r21, r1, portR21_OFFSET
113    swi r20, r1, portR20_OFFSET
114    swi r19, r1, portR19_OFFSET
115    swi r18, r1, portR18_OFFSET
116    swi r17, r1, portR17_OFFSET
117    swi r16, r1, portR16_OFFSET
118    swi r15, r1, portR15_OFFSET
119    /* R14 is saved later as it needs adjustment if a yield is performed. */
120    swi r13, r1, portR13_OFFSET
121    swi r12, r1, portR12_OFFSET
122    swi r11, r1, portR11_OFFSET
123    swi r10, r1, portR10_OFFSET
124    swi r9, r1, portR9_OFFSET
125    swi r8, r1, portR8_OFFSET
126    swi r7, r1, portR7_OFFSET
127    swi r6, r1, portR6_OFFSET
128    swi r5, r1, portR5_OFFSET
129    swi r4, r1, portR4_OFFSET
130    swi r3, r1, portR3_OFFSET
131    swi r2, r1, portR2_OFFSET
132
133    /* Stack the critical section nesting value. */
134    lwi r18, r0, uxCriticalNesting
135    swi r18, r1, portCRITICAL_NESTING_OFFSET
136
137    /* Stack MSR. */
138    mfs r18, rmsr
139    swi r18, r1, portMSR_OFFSET
140
141    #if( XPAR_MICROBLAZE_USE_FPU != 0 )
142        /* Stack FSR. */
143        mfs r18, rfsr
144        swi r18, r1, portFSR_OFFSET
145    #endif
146
147    /* Save the top of stack value to the TCB. */
148    lwi r3, r0, pxCurrentTCB
149    sw  r1, r0, r3
150
151    .endm
152
153.macro portRESTORE_CONTEXT
154
155    /* Load the top of stack value from the TCB. */
156    lwi r18, r0, pxCurrentTCB
157    lw  r1, r0, r18
158
159    /* Restore the general registers. */
160    lwi r31, r1, portR31_OFFSET
161    lwi r30, r1, portR30_OFFSET
162    lwi r29, r1, portR29_OFFSET
163    lwi r28, r1, portR28_OFFSET
164    lwi r27, r1, portR27_OFFSET
165    lwi r26, r1, portR26_OFFSET
166    lwi r25, r1, portR25_OFFSET
167    lwi r24, r1, portR24_OFFSET
168    lwi r23, r1, portR23_OFFSET
169    lwi r22, r1, portR22_OFFSET
170    lwi r21, r1, portR21_OFFSET
171    lwi r20, r1, portR20_OFFSET
172    lwi r19, r1, portR19_OFFSET
173    lwi r17, r1, portR17_OFFSET
174    lwi r16, r1, portR16_OFFSET
175    lwi r15, r1, portR15_OFFSET
176    lwi r14, r1, portR14_OFFSET
177    lwi r13, r1, portR13_OFFSET
178    lwi r12, r1, portR12_OFFSET
179    lwi r11, r1, portR11_OFFSET
180    lwi r10, r1, portR10_OFFSET
181    lwi r9, r1, portR9_OFFSET
182    lwi r8, r1, portR8_OFFSET
183    lwi r7, r1, portR7_OFFSET
184    lwi r6, r1, portR6_OFFSET
185    lwi r5, r1, portR5_OFFSET
186    lwi r4, r1, portR4_OFFSET
187    lwi r3, r1, portR3_OFFSET
188    lwi r2, r1, portR2_OFFSET
189
190    /* Reload the rmsr from the stack. */
191    lwi r18, r1, portMSR_OFFSET
192    mts rmsr, r18
193
194    #if( XPAR_MICROBLAZE_USE_FPU != 0 )
195        /* Reload the FSR from the stack. */
196        lwi r18, r1, portFSR_OFFSET
197        mts rfsr, r18
198    #endif
199
200    /* Load the critical nesting value. */
201    lwi r18, r1, portCRITICAL_NESTING_OFFSET
202    swi r18, r0, uxCriticalNesting
203
204    /* Test the critical nesting value.  If it is non zero then the task last
205    exited the running state using a yield.  If it is zero, then the task
206    last exited the running state through an interrupt. */
207    xori r18, r18, 0
208    bnei r18, exit_from_yield
209
210    /* r18 was being used as a temporary.  Now restore its true value from the
211    stack. */
212    lwi r18, r1, portR18_OFFSET
213
214    /* Remove the stack frame. */
215    addik r1, r1, portCONTEXT_SIZE
216
217    /* Return using rtid so interrupts are re-enabled as this function is
218    exited. */
219    rtid r14, 0
220    or r0, r0, r0
221
222    .endm
223
224/* This function is used to exit portRESTORE_CONTEXT() if the task being
225returned to last left the Running state by calling taskYIELD() (rather than
226being preempted by an interrupt). */
227    .text
228    .align  4
229exit_from_yield:
230
231    /* r18 was being used as a temporary.  Now restore its true value from the
232    stack. */
233    lwi r18, r1, portR18_OFFSET
234
235    /* Remove the stack frame. */
236    addik r1, r1, portCONTEXT_SIZE
237
238    /* Return to the task. */
239    rtsd r14, 0
240    or r0, r0, r0
241
242
243    .text
244    .align  4
245_interrupt_handler:
246
247    portSAVE_CONTEXT
248
249    /* Stack the return address. */
250    swi r14, r1, portR14_OFFSET
251
252    /* Switch to the ISR stack. */
253    lwi r1, r0, pulISRStack
254
255    /* The parameter to the interrupt handler. */
256    ori r5, r0, configINTERRUPT_CONTROLLER_TO_USE
257
258    /* Execute any pending interrupts. */
259    bralid r15, XIntc_DeviceInterruptHandler
260    or r0, r0, r0
261
262    /* See if a new task should be selected to execute. */
263    lwi r18, r0, ulTaskSwitchRequested
264    or r18, r18, r0
265
266    /* If ulTaskSwitchRequested is already zero, then jump straight to
267    restoring the task that is already in the Running state. */
268    beqi r18, task_switch_not_requested
269
270    /* Set ulTaskSwitchRequested back to zero as a task switch is about to be
271    performed. */
272    swi r0, r0, ulTaskSwitchRequested
273
274    /* ulTaskSwitchRequested was not 0 when tested.  Select the next task to
275    execute. */
276    bralid r15, vTaskSwitchContext
277    or r0, r0, r0
278
279task_switch_not_requested:
280
281    /* Restore the context of the next task scheduled to execute. */
282    portRESTORE_CONTEXT
283
284
285    .text
286    .align  4
287VPortYieldASM:
288
289    portSAVE_CONTEXT
290
291    /* Modify the return address so a return is done to the instruction after
292    the call to VPortYieldASM. */
293    addi r14, r14, 8
294    swi r14, r1, portR14_OFFSET
295
296    /* Switch to use the ISR stack. */
297    lwi r1, r0, pulISRStack
298
299    /* Select the next task to execute. */
300    bralid r15, vTaskSwitchContext
301    or r0, r0, r0
302
303    /* Restore the context of the next task scheduled to execute. */
304    portRESTORE_CONTEXT
305
306    .text
307    .align  4
308vPortStartFirstTask:
309
310    portRESTORE_CONTEXT
311
312
313
314#if ( MICROBLAZE_EXCEPTIONS_ENABLED == 1 ) && ( configINSTALL_EXCEPTION_HANDLERS == 1 )
315
316    .text
317    .align 4
318vPortExceptionHandlerEntry:
319
320    /* Take a copy of the stack pointer before vPortExecptionHandler is called,
321    storing its value prior to the function stack frame being created. */
322    swi r1, r0, pulStackPointerOnFunctionEntry
323    bralid r15, vPortExceptionHandler
324    or r0, r0, r0
325
326#endif /* ( MICROBLAZE_EXCEPTIONS_ENABLED == 1 ) && ( configINSTALL_EXCEPTION_HANDLERS == 1 ) */
327