From 33e4744d1c73c9f5512abb4010e4cc81763ab3a2 Mon Sep 17 00:00:00 2001
From: cheapie <cheapiephp@gmail.com>
Date: Fri, 19 Jun 2026 22:38:28 -0500
Subject: Add machine timer interrupt

---
 assembly/timer-test/timer-test.S | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 assembly/timer-test/timer-test.S

(limited to 'assembly/timer-test/timer-test.S')

diff --git a/assembly/timer-test/timer-test.S b/assembly/timer-test/timer-test.S
new file mode 100644
index 0000000..e114f3f
--- /dev/null
+++ b/assembly/timer-test/timer-test.S
@@ -0,0 +1,36 @@
+la t0,handler
+csrw mtvec,t0 # Set trap handler address and mode (0/direct)
+li t0,0x400
+csrc mstatush,t0 # Enable trap handler
+li t0,0x80
+csrw mie,t0 # Enable machine timer interrupt and disable others
+
+la t0,mmio
+csrw 0x801,t0 # Set up MMIO base address
+
+lw t1,2(t0) # Read current time
+addi t1,t1,5
+sw t1,10(t0) # Set mtimecmp to 5 seconds in the future
+
+csrsi mstatus,8 # Enable interrupts globally
+
+wfi # Wait for the interrupt to trigger
+
+li a7,10 # Exit program
+ecall
+
+.balign 4
+handler:
+li t1,-1
+sw t1,10(t0) # Set mtimecmp to the distant future
+csrr a0,mcause
+li a7,1 # Print integer
+ecall
+
+li a0,'\n'
+li a7,11 # Print character
+ecall
+
+mret
+
+mmio:
-- 
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