From bfd7592c10befe0ba086f15bf169ab85a311a75e Mon Sep 17 00:00:00 2001
From: Nathan Lee <me@nwlee.tech>
Date: Mon, 24 Aug 2026 20:23:16 -0500
Subject: add floating point error CSR

---
 src/core.rs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

(limited to 'src/core.rs')

diff --git a/src/core.rs b/src/core.rs
index 2746d1b..24c6a8f 100644
--- a/src/core.rs
+++ b/src/core.rs
@@ -388,8 +388,12 @@ pub fn fdiv_s(state: &mut CpuState, rd: usize, rs1: usize, rs2: usize) {
     let b = state.f_registers[rs2];
 
     state.f_registers[rd] = if b == 0.0 {
-        f32::NAN
-        // todo: raise division by zero in csr
+        state.csr[0x001 /*fflags*/] |= 0b100;
+        if a.is_sign_positive() {
+            f32::INFINITY
+        } else {
+            f32::NEG_INFINITY
+        }
     } else {
         a / b
     }
-- 
cgit v1.2.3