diff --git a/hw/xbox/nv2a/pgraph/glsl/vsh-prog.c b/hw/xbox/nv2a/pgraph/glsl/vsh-prog.c
index e496f83e88..efb2dd8ff0 100644
--- a/hw/xbox/nv2a/pgraph/glsl/vsh-prog.c
+++ b/hw/xbox/nv2a/pgraph/glsl/vsh-prog.c
@@ -209,6 +209,7 @@ static bool ilu_force_scalar[] = {
     false,
 };
 
+#define OUTPUT_REG_POS 0
 #define OUTPUT_REG_FOG 5
 
 static const char* out_reg_name[] = {
@@ -304,7 +305,6 @@ static MString *decode_opcode_input(const uint32_t *shader_token,
 
     MString *ret_str = mstring_new();
 
-
     if (vsh_get_field(shader_token, neg_field) > 0) {
         mstring_append_fmt(ret_str, "-");
     }
@@ -354,6 +354,7 @@ static MString *decode_opcode(const uint32_t *shader_token,
     MString *ret = mstring_new();
     int reg_num = vsh_get_field(shader_token, FLD_OUT_R);
     bool use_temp_var = false;
+    bool use_temp_opos = false;
 
     /* Test for paired opcodes (in other words : Are both <> NOP?) */
     if (out_mux == OMUX_MAC
@@ -369,6 +370,8 @@ static MString *decode_opcode(const uint32_t *shader_token,
         reg_num = 1;
     }
 
+    const char *write_mask_str = NULL;
+
     /* See if we must add a muxed opcode too: */
     if (vsh_get_field(shader_token, FLD_OUT_MUX) == out_mux
         /* Only if it's not masked away: */
@@ -386,12 +389,18 @@ static MString *decode_opcode(const uint32_t *shader_token,
                                    shader_token, FLD_OUT_ADDRESS)));
         } else {
             int out_reg = vsh_get_field(shader_token, FLD_OUT_ADDRESS) & 0xF;
-            mstring_append(ret,out_reg_name[out_reg]);
+            if (out_reg == OUTPUT_REG_POS && (use_temp_var || mask)) {
+                use_temp_opos = true;
+                mstring_append(ret, "_temp_r12");
+            } else {
+                mstring_append(ret, out_reg_name[out_reg]);
+            }
             write_fog_register = out_reg == OUTPUT_REG_FOG;
         }
 
         int write_mask = vsh_get_field(shader_token, FLD_OUT_O_MASK);
-        const char *write_mask_str = write_fog_register ? fog_mask_str[write_mask] : mask_str[write_mask];
+        write_mask_str = write_fog_register ? fog_mask_str[write_mask]
+                                            : mask_str[write_mask];
         mstring_append(ret, write_mask_str);
         mstring_append(ret, inputs);
         mstring_append(ret, ");\n");
@@ -428,6 +437,16 @@ static MString *decode_opcode(const uint32_t *shader_token,
         }
     }
 
+    if (use_temp_opos) {
+        if (!*suffix) {
+            *suffix = mstring_new();
+        }
+        assert(write_mask_str && "Temp oPos flagged without a mask");
+        const char *write_mask_components = write_mask_str + 1;
+        mstring_append_fmt(*suffix, "  oPos.%s = _temp_r12.%s;\n",
+                           write_mask_components, write_mask_components);
+    }
+
     return ret;
 }
 
@@ -451,7 +470,7 @@ static MString *decode_token(const uint32_t *shader_token)
                             (vsh_get_field(shader_token, FLD_C_R_HIGH) << 2)
                                 | vsh_get_field(shader_token, FLD_C_R_LOW));
 
-    MString *mac_suffix = NULL;
+    MString *suffix = NULL;
     if (mac != MAC_NOP) {
         MString *inputs_mac = mstring_new();
         if (mac_opcode_params[mac].A) {
@@ -485,7 +504,7 @@ static MString *decode_token(const uint32_t *shader_token)
                             vsh_get_field(shader_token, FLD_OUT_MAC_MASK),
                             mac_opcode[mac],
                             mstring_get_str(inputs_mac),
-                            &mac_suffix);
+                            &suffix);
         mstring_unref(inputs_mac);
     } else {
         ret = mstring_new();
@@ -502,7 +521,7 @@ static MString *decode_token(const uint32_t *shader_token)
                           vsh_get_field(shader_token, FLD_OUT_ILU_MASK),
                           ilu_opcode[ilu],
                           mstring_get_str(inputs_c),
-                          NULL);
+                          &suffix);
 
         mstring_append(ret, mstring_get_str(ilu_op));
 
@@ -512,9 +531,9 @@ static MString *decode_token(const uint32_t *shader_token)
 
     mstring_unref(input_c);
 
-    if (mac_suffix) {
-        mstring_append(ret, mstring_get_str(mac_suffix));
-        mstring_unref(mac_suffix);
+    if (suffix) {
+        mstring_append(ret, mstring_get_str(suffix));
+        mstring_unref(suffix);
     }
 
     return ret;
@@ -543,6 +562,11 @@ static const char* vsh_header =
     "vec4 _temp_vec;\n"
     "int _temp_addr;\n"
 
+    /* Used to emulate concurrency of multi-output / paired instructions that
+     * write to oPos and read from R12
+     */
+    "vec4 _temp_r12;\n"
+
     /* See:
      * http://msdn.microsoft.com/en-us/library/windows/desktop/bb174703%28v=vs.85%29.aspx
      * https://www.opengl.org/registry/specs/NV/vertex_program1_1.txt