Hello,
I'm using Zynq Z7020 SoC with C++ compiler.
I was got strange behavior in the following code (brack point line 11):
#include <iostream>
#include "FreeRTOS.h"
#include "task.h"
#include "xparameters.h"
void foo(double first, double second)
{
if (first != second)
first += second;
}
void firstTask(void*)
{
double testValue2 = 0.0;
while(true) {
foo(testValue2, testValue2);
testValue2 += 42.2;
if (testValue2 > 100)
testValue2 = 0.0;
}
}
void secondTask(void*)
{
double testValue1 = 12.7;
while(true) {
vTaskDelay(1000 / portTICK_PERIOD_MS);
std::cout << testValue1 << std::endl;
}
}
int main()
{
xTaskCreate(firstTask, "firstTask", 1024, nullptr, 2, nullptr);
xTaskCreate(secondTask, "secondTask", 1024, nullptr, 2, nullptr);
vTaskStartScheduler();
while(true) continue;
return 0;
}The first and second value not equal(first = 12.7, second = 0.0). Arguments transmit to function foo use registers d0 and d1(see below). This looks like registers weren't restored after interrupt.
From stack call
brack point here: first += second;
// ----------------------------------------------------------------------------
state from line 18( foo(testValue2, testValue2); )
r11 = 0x001c94b4
[r11, #-12] = 0x001c94a8
memory:
0x001c94a8 : 0x1C94A8 <Hex Integer>
Address 0 - 3 4 - 7 8 - B C - F
001C94A0 10101010 00000000 00000000 00000000
001C94B0 11111111 00000000 00000000 00000000
001C94C0 00000000 A5A5A5A5 00000000 80000060
001C94D0 001C9454 00000000 001C83A8 001C83A8
001C94E0 001C94D0 001C83A0 00000006 00000000
001C94F0 00000000 001C94D0 00000000 00000002
001C9500 001C84C8 73726966 73615474 0000006B
001C9510 00000001 00000000 00000002 00000000
001C9520 00000000 00000000 00000000 80001008
001C9530 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9540 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9550 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9560 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9570 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9580 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9590 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C95A0 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C95B0 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C95C0 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C95D0 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
ASM:
firstTask:
00100d04: push {r11,lr}
00100d08: add r11, sp, #4
00100d0c: sub sp, sp, #16
00100d10: str r0, [r11, #-16]
16 double testValue2 = 0.0;
17 while(true) {
00100d14: mov r2, #0
00100d18: mov r3, #0
00100d1c: strd r2, r3, [r11, #-12]
18 foo(testValue2, testValue2);
00100d20: vldr d1, [r11, #-12]
00100d24: vldr d0, [r11, #-12]
00100d28: bl -116 ; addr=0x00100cbc: foo
19 testValue2 += 42.2;
00100d2c: vldr d16, [r11, #-12]
00100d30: vldr d17, [pc, #+40]
00100d34: vadd.f64 d16, d16, d17
00100d38: vstr d16, [r11, #-12]
// ----------------------------------------------------------------------------
state from line 11( first += second; )
r11 = 0x001c949c
[r11, #-12] = 0x001c9490
[r11, #-20] = 0x001c9488
memory:
0x001c9488 : 0x1C9488 <Hex Integer>
Address 0 - 3 4 - 7 8 - B C - F
001C9480 09090909 10101010 00000000 00000000
001C9490 66666666 40296666 2000001F 001C94B4
001C94A0 10101010 00000000 00000000 00000000
001C94B0 11111111 00000000 00000000 00000000
001C94C0 00000000 A5A5A5A5 00000000 80000060
001C94D0 001C9454 00000000 001C83A8 001C83A8
001C94E0 001C94D0 001C83A0 00000006 00000000
001C94F0 00000000 001C94D0 00000000 00000002
001C9500 001C84C8 73726966 73615474 0000006B
001C9510 00000001 00000000 00000002 00000000
001C9520 00000000 00000000 00000000 80001008
001C9530 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9540 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9550 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9560 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9570 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9580 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C9590 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C95A0 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
001C95B0 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5
ASM:
foo:
00100cbc: push {r11}
00100cc0: add r11, sp, #0
00100cc4: sub sp, sp, #20
00100cc8: vstr d0, [r11, #-12]
00100ccc: vstr d1, [r11, #-20]
10 if (first != second)
00100cd0: vldr d17, [r11, #-12]
00100cd4: vldr d16, [r11, #-20]
00100cd8: vcmp.f64 d17, d16
00100cdc: vmrs APSR_nzcv, fpscrI don't have more ideas about what wrong. Maybe somebody has ideas?
