From a7d879a485cfd133e66faa3fef2b99155d264ef8 Mon Sep 17 00:00:00 2001
From: inglorion <voodoo@inglorion.net>
Date: Sat, 2 Feb 2013 19:11:50 -0800
Subject: [PATCH] implemented {save,restore}-frame and {save,restore}-locals on
 AMD64

---
 lib/voodoo/generators/amd64_nasm_generator.rb | 10 ++++-
 lib/voodoo/generators/nasm_generator.rb       | 53 +++++++++++++++++++++++----
 2 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/lib/voodoo/generators/amd64_nasm_generator.rb b/lib/voodoo/generators/amd64_nasm_generator.rb
index ba34eca..f9ce164 100644
--- a/lib/voodoo/generators/amd64_nasm_generator.rb
+++ b/lib/voodoo/generators/amd64_nasm_generator.rb
@@ -1,4 +1,5 @@
 require 'voodoo/generators/nasm_generator'
+require 'set'
 
 module Voodoo
   # = AMD64 NASM Code Generator
@@ -85,6 +86,7 @@ module Voodoo
       # Registers used to store locals
       @LOCAL_REGS = [:r12, :r13, :r14, :r15]
       @NLOCAL_REGS = @LOCAL_REGS.length
+      @LOCAL_REGISTERS_SET = Set.new @LOCAL_REGS
       # Accumulator index
       @AX = :rax
       # Base index
@@ -97,7 +99,11 @@ module Voodoo
       @BP = :rbp
       # Stack pointer
       @SP = :rsp
-      @SAVE_FRAME_REGISTERS = [:rbx, :r12, :r13, :r14, :r15, :rsp, :rbp]
+      @SAVED_FRAME_LAYOUT = {
+        :rbx => 0, :r12 => 1, :r13 => 2, :r14 => 3, :r15 => 4,
+        :rsp => 5, :rbp => 6,
+      }
+      @SAVE_FRAME_REGISTERS = @SAVED_FRAME_LAYOUT.keys
       super params
       @features.merge! \
         :'bits-per-word' => '64',
@@ -306,7 +312,7 @@ module Voodoo
       if n < @NLOCAL_REGS
         @LOCAL_REGS[n]
       else
-        (n - @NLOCAL_REGS + number_of_register_arguments + 1) * -@WORDSIZE
+        (n + number_of_register_arguments + 1) * -@WORDSIZE
       end
     end
 
diff --git a/lib/voodoo/generators/nasm_generator.rb b/lib/voodoo/generators/nasm_generator.rb
index 75518cb..64964d3 100644
--- a/lib/voodoo/generators/nasm_generator.rb
+++ b/lib/voodoo/generators/nasm_generator.rb
@@ -235,25 +235,62 @@ module Voodoo
     # Saving and restoring frames.
     #
 
+    # Given some local variable names, returns the registers those variables
+    # are stored in. If no variable names are given, returns all registers
+    # used to store local variables.
+    def registers_for_locals locals = []
+      locals = @environment.symbols.keys if locals.empty?
+      registers = []
+      locals.each do |sym|
+        reg = @environment[sym]
+        registers << reg if @LOCAL_REGISTERS_SET.include? @environment[sym]
+      end
+      registers
+    end
+
     # Restores the frame saved at the given location.
-    def restore_frame location
-      load_value_into_register location, @SCRATCH_REG
-      @SAVE_FRAME_REGISTERS.each_with_index do |register,i|
+    def restore_frame frame
+      restore_registers_from_frame frame, @SAVE_FRAME_REGISTERS
+    end
+    
+    # Restores local variables from a saved frame.
+    def restore_locals frame, *locals
+      restore_registers_from_frame frame, registers_for_locals(locals)
+    end
+
+    # Helper function for restore_frame and restore_locals.
+    def restore_registers_from_frame frame, registers
+      load_value_into_register frame, @SCRATCH_REG
+      registers.each do |register|
+        i = @SAVED_FRAME_LAYOUT[register]
 	emit "mov #{register}, [#{@SCRATCH_REG} + #{i} * #{@WORDSIZE}]\n"
       end
     end
     
     # Saves the current frame to the given location.
-    def save_frame location
-      load_value_into_register location, @SCRATCH_REG
-      @SAVE_FRAME_REGISTERS.each_with_index do |register,i|
+    def save_frame frame
+      save_registers_to_frame frame, @SAVE_FRAME_REGISTERS
+    end
+
+    # Saves local variables to the given frame.
+    # If no locals are specified, saves all locals.
+    # If locals are specified, saves only the specified ones.
+    def save_locals frame, *locals
+      save_registers_to_frame frame, registers_for_locals(locals)
+    end
+    
+    # Helper function for save_frame and save_locals.
+    def save_registers_to_frame frame, registers
+      load_value_into_register frame, @SCRATCH_REG
+      registers.each do |register|
+        i = @SAVED_FRAME_LAYOUT[register]
 	emit "mov [#{@SCRATCH_REG} + #{i} * #{@WORDSIZE}], #{register}\n"
       end
     end
-    
+
     # Returns the number of bytes necessary to save the current frame.
     def saved_frame_size
-      @SAVE_FRAME_REGISTERS.length * @WORDSIZE
+      @SAVED_FRAME_LAYOUT.length * @WORDSIZE
     end
 
     #
-- 
2.11.4.GIT