diff --git a/src/lib/modelasm_c.c b/src/lib/modelasm_c.c
index c6a92477e..c443b9b91 100644
--- a/src/lib/modelasm_c.c
+++ b/src/lib/modelasm_c.c
@@ -1616,7 +1616,7 @@ f32 sinf(f32 radians)
 		if (t0 < 310) {
 			f14 = radians * 0.31830987334251f;
 
-			t1 = (s32) (f14 + 0.5f);
+			t1 = (s32) (f14 > 0.0f ? f14 + 0.5f : f14 - 0.5f);
 			f14 = t1;
 
 			f15 = M_PI;