Fix CLOCK_FREQ.

os/src/config.rs

@@ -12,4 +12,4 @@ pub const TRAP_CONTEXT: usize = TRAMPOLINE - PAGE_SIZE;
 pub const CLOCK_FREQ: usize = 403000000 / 62;
 
 #[cfg(feature = "board_qemu")]
-pub const CPU_FREQ: usize = 12500000;
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+pub const CLOCK_FREQ: usize = 12500000;
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os/src/timer.rs

 use riscv::register::time;
 use crate::sbi::set_timer;
-use crate::config::CPU_FREQ;
+use crate::config::CLOCK_FREQ;
 
 const TICKS_PER_SEC: usize = 100;
 const MSEC_PER_SEC: usize = 1000;
@@ -10,9 +10,9 @@ pub fn get_time() -> usize {
 }
 
 pub fn get_time_ms() -> usize {
-    time::read() / (CPU_FREQ / MSEC_PER_SEC)
+    time::read() / (CLOCK_FREQ / MSEC_PER_SEC)
 }
 
 pub fn set_next_trigger() {
-    set_timer(get_time() + CPU_FREQ / TICKS_PER_SEC);
+    set_timer(get_time() + CLOCK_FREQ / TICKS_PER_SEC);
 }
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