diff align8.h @ 1:6422640a802f

first upload

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/align8.h	Tue Oct 05 10:45:57 2010 +0100
@@ -0,0 +1,39 @@
+//---------------------------------------------------------------------------
+
+#ifndef align8H
+#define align8H
+
+/*
+  align8.cpp - 8-byte (64-bit) alignment routines.
+
+  This file provides tools for aligning boundaries of arrays, particularly of 64-byte units, e.g. double-
+  precision floating points, to physical addresses divisible by 8, including aligning dynamically
+  allocated memory block and aligning call stack. Currently stack alignment is disabled due to lack
+  of compiler support for Intel assembly.
+
+  Further reading: "Double precision floating point alignment issue.pdf"
+*/
+
+//--stack alignment----------------------------------------------------------
+/*
+  These two macros are used to envelop a function call so that the function is called with a stack
+  pointer that is a multiple of 8. Aligning the stack does not automatically ensure that local double
+  -precision floating-point variables (or other variables one wants to align to 8-byte boundaries) are
+  aligned to 8-byte boundaries; one has to adjust the variable declaration order, using dummy variables
+  if necessary, to make the alignment happen.
+*/
+//macro ALIGN_STACK_8 moves the current stack pointer to a multiple of 8
+#define ALIGN_STACK_8 {int alignstack; asm {mov alignstack, esp} asm {and esp, 0xFFFFFFF8}
+//macro RESTORE_STACK moves the stack pointer back to where it was before ALIGN_STACK_8
+#define RESTORE_STACK asm {mov esp, alignstack}}
+
+//ALIGN8 ensures F is executed with a start stack pointer divisible by 8. Currently disabled.
+#define ALIGN8(F) F
+//uncomment the following line to enable stack alignment
+//#define ALIGN8(F) ALIGN_STACK_8 F RESTORE_STACK
+
+//--64-bit aligned memory allocation routines--------------------------------
+void* malloc8(unsigned size);
+void free8(void* buffer8);
+
+#endif