Add new file

svn path=/trunk/mono/; revision=22663

diff --git a/docs/ir-desc b/docs/ir-desc
new file mode 100644 (file)
index 0000000..25ad5c1
--- /dev/null
+++ b/docs/ir-desc
@@ -0,0 +1,30 @@
+Mono Intermediate Representation Documentation
+
+Operation: OP_LOCALLOC
+       inst_left:
+               The value 
+                                ins->inst_left = *sp;
+                                ins->cil_code = ip;
+
+       This is the equivalent of alloca() in a C implementation: it
+       allocates a bunch of bytes on the stack dynamically. Local
+       variables are allocated statically in the stack instead.
+       
+       It is implemented by moving the stack pointer according to the
+       platform ABI: you may need to keep a specific frame register
+       to address local variables when LOCALLOC is used (the PPC code
+       does this, for example: ifyou're doing the s390 port I suggest
+       starting from that)
+
+Operation: OP_CALL_HANDLER.
+
+       cil_code: 
+               Points to the CIL where the LEAVE or LEAVE_S
+               instruction was found.
+
+       inst_target_bb:
+               The target basic block for this invocation.
+
+       This instruction must call the target basic block.
+       
+       
\ No newline at end of file