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fixed ISR memory alignement

This commit is contained in:
mariusmonton 2019-01-22 13:26:41 +01:00
parent d83a15eec5
commit e9ef03890f
3 changed files with 29 additions and 19 deletions
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3
tests/C/timer/compile.sh Normal file
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@ -0,0 +1,3 @@
riscv32-unknown-elf-gcc -Wall -I. -O0 -static -march=rv32imac -mabi=ilp32 --specs=nosys.specs timer.c timerasm.S -o timer.elf
objcopy -Oihex timer.elf timer.hex
riscv32-unknown-elf-objdump timer.elf -d > dump

40
tests/C/timer/timer.c
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@ -1,10 +1,10 @@
#include <stdio.h> #include <stdio.h>
#define TIMER (*(uint64_t *)0x40004000) #define TIMER (*(uint64_t volatile *)0x40004000)
#define TIMER_CMP (*(uint64_t *)0x40004008) #define TIMER_CMP (*(uint64_t volatile *)0x40004008)
#define TRACE (*(unsigned char *)0x40000000) #define TRACE (*(unsigned char volatile *)0x40000000)
volatile int ticks = 0; volatile uint32_t ticks = 0;
int _write(int file, const char *ptr, int len) { int _write(int file, const char *ptr, int len) {
int x; int x;
@ -17,20 +17,22 @@ int _write(int file, const char *ptr, int len) {
} }
void timer_ISR() { void timer_ISR() {
uint32_t timer_value; volatile uint32_t timer_value;
ticks++; ticks++;
if (ticks < 10) {
timer_value = TIMER; timer_value = TIMER;
// timer is in nanoseconds, set to 1 ms.
// comparator value fixed to take into account number of instructions executed // timer is in nanoseconds, set to 1 ms.
TIMER_CMP = timer_value + 590; // comparator value fixed to take into account number of instructions executed
} TIMER_CMP = timer_value + 610;
} }
void register_timer_isr() { void register_timer_isr() {
asm volatile("la t0, TIMER_CMP_INT \n csrw mtvec, t0"); asm volatile("la t0, TIMER_CMP_INT");
asm volatile("li t1, 0x888 \n csrw mie, t1"); asm volatile("csrw mtvec, t0");
asm volatile("li t1, 0x888");
asm volatile("csrw mie, t1");
} }
int main(void) { int main(void) {
@ -43,14 +45,20 @@ int main(void) {
start_time = TIMER; start_time = TIMER;
TIMER_CMP = start_time + 10000; TIMER_CMP = start_time + 10000;
printf("set timer to %ld ns\n", start_time + 10000); printf("set timer to %ld ns\n", start_time + 10000);
do { do {
timer_value = TIMER; timer_value = TIMER;
} while (timer_value < start_time + 200000); } while (timer_value < start_time + 2000000);
printf("Timer: %ld ns\n", timer_value); printf("Timer: %ld ns\n", timer_value);
printf("ticks: %ld\n", ticks); printf("ticks: %ld\n", ticks);
if (ticks > 2100) {
printf("Test OK!\n");
}
printf("Finish\n");
asm volatile ("ecall"); asm volatile ("ecall");
return 0; return 0;
} }

5
tests/C/timer/timerasm.S
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@ -8,7 +8,7 @@
#define LOAD lw #define LOAD lw
#define REGBYTES 4 #define REGBYTES 4
.align 2
TIMER_CMP_INT: TIMER_CMP_INT:
/* store execution context on the stack (register content) */ /* store execution context on the stack (register content) */
addi sp, sp, -REGBYTES * 32 addi sp, sp, -REGBYTES * 32
@ -32,7 +32,7 @@ STORE x31, 30 * REGBYTES(sp)
/* load interrupt/trap reason and call external C function to handle it */ /* load interrupt/trap reason and call external C function to handle it */
csrr a0, mcause csrr a0, mcause
jal timer_ISR jal timer_ISR
/* re-store the saved context */ /* re-store the saved context */
LOAD x1, 0x0(sp) LOAD x1, 0x0(sp)
@ -54,4 +54,3 @@ LOAD x30, 29 * REGBYTES(sp)
LOAD x31, 30 * REGBYTES(sp) LOAD x31, 30 * REGBYTES(sp)
addi sp, sp, REGBYTES * 32 addi sp, sp, REGBYTES * 32
mret mret