X-Git-Url: http://wien.tomnetworks.com/gitweb/?a=blobdiff_plain;f=docs%2Fmini-doc.txt;h=ba19c1031f112256c83295ebe53f2ecf6dfb8680;hb=e78b5e75cc532a49cbd64c91fa9b7c3fdbeb8529;hp=30d9b4442b7ad5cc8c24bb5c2f67e04f5ab88008;hpb=ce581fac4e962f9ada55d8b8c3f8d34a4cdc23e2;p=mono.git

diff --git a/docs/mini-doc.txt b/docs/mini-doc.txt
index 30d9b4442b7..ba19c1031f1 100644
--- a/docs/mini-doc.txt
+++ b/docs/mini-doc.txt
@@ -4,7 +4,15 @@
 	   Miguel de Icaza (miguel@{ximian.com,gnome.org}),
 	   Paolo Molaro (lupus@{ximian.com,debian.org})
 
-  
+	This documents overall design of the Mono JIT up to version
+	2.0.   After Mono 2.0 the JIT engine was upgraded from
+	a tree-based intermediate representation to a linear
+	intermediate representation.
+
+	The Linear IL is documented here:
+
+	    http://www.mono-project.com/Linear_IL
+
 * Abstract
 
 	Mini is a new compilation engine for the Mono runtime.  The
@@ -70,6 +78,24 @@
 	CIL code on the fly to marshal parameters, and then this
 	code is in turned processed by the JIT engine.
 
+	Mono has now gone through three different JIT engines, these
+	are:
+
+	* Original JIT engine: 2002, hard to port, hard to
+	  implement optimizations.
+
+	* Second JIT engine, used up until Mono 2.0, very
+          portable, many new optimizations.
+
+	* Third JIT engine, replaced the code generation layer from
+	  being based on a tree representation to be based on a linear
+	  representation.
+
+        For more information on the code generation changes, see our
+	web site for the details on the Linear IL:
+
+	    http://www.mono-project.com/Linear_IL
+
 * Previous Experiences
 
 	Mono has built a JIT engine, which has been used to bootstrap
@@ -162,7 +188,7 @@
 	application domains, or generate code that will not be shared
 	across application domains.
 
-* Objectives of the new JIT engine.
+* Second Generation JIT engine.
 
 	We wanted to support a number of features that were missing:
 
@@ -206,7 +232,7 @@
 	     necessary that the JIT engine works in most of today's
 	     commercial hardware platforms. 
 
-* Features of the new JIT engine.
+* Features of the Second JIT engine.
 
 	The new JIT engine was architected by Dietmar Maurer and Paolo
 	Molaro, based on the new objectives.
@@ -375,13 +401,14 @@
 	variables to registers.  The linear scan pass uses the
 	information that was previously gathered by the loop nesting
 	and loop structure computation to favor variables in inner
-	loops. 
+	loops.   This process updates the basic block `nesting' field
+	which is later used during liveness analysis.
 
 	Stack space is then reserved for the local variables and any
 	temporary variables generated during the various
 	optimizations.
 
-** Instruction selection 
+** Instruction selection: Only used up until Mono 2.0
 
 	At this point, the BURS instruction selector is invoked to
 	transform the tree-based representation into a list of
@@ -489,7 +516,9 @@
 	operations if possible.
 
 	The rest of the code generation is fairly simple: a switch
-	statement is used to generate code for each of the MonoInsts
+	statement is used to generate code for each of the MonoInsts,
+	in the mono/mini/mini-ARCH.c files, the method is called
+	"mono_arch_output_basic_block".
 
 	We always try to allocate code in sequence, instead of just using
 	malloc. This way we increase spatial locality which gives a massive
@@ -606,7 +635,7 @@
 	registers, fixed registers and clobbered registers by each
 	operation.
 
-* BURG Code Generator Generator
+* BURG Code Generator Generator: Only used up to Mono 2.0
 
        monoburg was written by Dietmar Maurer. It is based on the
        papers from Christopher W. Fraser, Robert R. Henry and Todd
@@ -765,4 +794,4 @@
 	processors, and some of the framework exists today in our
 	register allocator and the instruction selector to cope with
 	this, but has not been finished.  The instruction selection
-	would happen at the same time as local register allocation. <
\ No newline at end of file
+	would happen at the same time as local register allocation. <