1 files changed, 123 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_eu.c b/src/mesa/drivers/dri/i965/brw_eu.c
index b3ae4eef334..c53efba5991 100644
--- a/src/mesa/drivers/dri/i965/brw_eu.c
+++ b/src/mesa/drivers/dri/i965/brw_eu.c
@@ -129,3 +129,126 @@ const GLuint *brw_get_program( struct brw_compile *p,
    return (const GLuint *)p->store;
 }
 
+
+
+/**
+ * Subroutine calls require special attention.
+ * Mesa instructions may be expanded into multiple hardware instructions
+ * so the prog_instruction::BranchTarget field can't be used as an index
+ * into the hardware instructions.
+ *
+ * The BranchTarget field isn't needed, however.  Mesa's GLSL compiler
+ * emits CAL and BGNSUB instructions with labels that can be used to map
+ * subroutine calls to actual subroutine code blocks.
+ *
+ * The structures and function here implement patching of CAL instructions
+ * so they jump to the right subroutine code...
+ */
+
+
+/**
+ * For each OPCODE_BGNSUB we create one of these.
+ */
+struct brw_glsl_label
+{
+   const char *name; /**< the label string */
+   GLuint position;  /**< the position of the brw instruction for this label */
+   struct brw_glsl_label *next;  /**< next in linked list */
+};
+
+
+/**
+ * For each OPCODE_CAL we create one of these.
+ */
+struct brw_glsl_call
+{
+   GLuint call_inst_pos;  /**< location of the CAL instruction */
+   const char *sub_name;  /**< name of subroutine to call */
+   struct brw_glsl_call *next;  /**< next in linked list */
+};
+
+
+/**
+ * Called for each OPCODE_BGNSUB.
+ */
+void
+brw_save_label(struct brw_compile *c, const char *name, GLuint position)
+{
+   struct brw_glsl_label *label = CALLOC_STRUCT(brw_glsl_label);
+   label->name = name;
+   label->position = position;
+   label->next = c->first_label;
+   c->first_label = label;
+}
+
+
+/**
+ * Called for each OPCODE_CAL.
+ */
+void
+brw_save_call(struct brw_compile *c, const char *name, GLuint call_pos)
+{
+   struct brw_glsl_call *call = CALLOC_STRUCT(brw_glsl_call);
+   call->call_inst_pos = call_pos;
+   call->sub_name = name;
+   call->next = c->first_call;
+   c->first_call = call;
+}
+
+
+/**
+ * Lookup a label, return label's position/offset.
+ */
+static GLuint
+brw_lookup_label(struct brw_compile *c, const char *name)
+{
+   const struct brw_glsl_label *label;
+   for (label = c->first_label; label; label = label->next) {
+      if (strcmp(name, label->name) == 0) {
+         return label->position;
+      }
+   }
+   abort();  /* should never happen */
+   return ~0;
+}
+
+
+/**
+ * When we're done generating code, this function is called to resolve
+ * subroutine calls.
+ */
+void
+brw_resolve_cals(struct brw_compile *c)
+{
+    const struct brw_glsl_call *call;
+
+    for (call = c->first_call; call; call = call->next) {
+        const GLuint sub_loc = brw_lookup_label(c, call->sub_name);
+	struct brw_instruction *brw_call_inst = &c->store[call->call_inst_pos];
+	struct brw_instruction *brw_sub_inst = &c->store[sub_loc];
+	GLint offset = brw_sub_inst - brw_call_inst;
+
+	/* patch brw_inst1 to point to brw_inst2 */
+	brw_set_src1(brw_call_inst, brw_imm_d(offset * 16));
+    }
+
+    /* free linked list of calls */
+    {
+        struct brw_glsl_call *call, *next;
+        for (call = c->first_call; call; call = next) {
+	    next = call->next;
+	    _mesa_free(call);
+	}
+	c->first_call = NULL;
+    }
+
+    /* free linked list of labels */
+    {
+        struct brw_glsl_label *label, *next;
+	for (label = c->first_label; label; label = next) {
+	    next = label->next;
+	    _mesa_free(label);
+	}
+	c->first_label = NULL;
+    }
+}