shader: Add support for "negative" and unaligned offsets

"Negative" offsets don't exist. They are shown as such due to a bug in
nvdisasm.

Unaligned offsets have been proved to read the aligned offset. For
example, when reading an U32, if the offset is 6, the offset read will
be 4.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_context_get_set.cpp b/src/shader_recompiler/backend/glasm/emit_glasm_context_get_set.cpp
index 787612def..9ad668b86 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_context_get_set.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_context_get_set.cpp
@@ -18,6 +18,14 @@ void GetCbuf(EmitContext& ctx, IR::Inst& inst, const IR::Value& binding, ScalarU
         throw NotImplementedException("Indirect constant buffer loading");
     }
     const Register ret{ctx.reg_alloc.Define(inst)};
+    if (offset.type == Type::U32) {
+        // Avoid reading arrays out of bounds, matching hardware's behavior
+        const u32 imm_offset{offset.imm_u32};
+        if (offset.imm_u32 >= 0x10'000) {
+            ctx.Add("MOV.S {},0;", ret);
+            return;
+        }
+    }
     ctx.Add("LDC.{} {},c{}[{}];", size, ret, binding.U32(), offset);
 }