#!/usr/bin/env python

# (C) Copyright IBM Corporation 2005
# All Rights Reserved.
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# on the rights to use, copy, modify, merge, publish, distribute, sub
# license, and/or sell copies of the Software, and to permit persons to whom
# the Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice (including the next
# paragraph) shall be included in all copies or substantial portions of the
# Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
# IBM AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.
#
# Authors:
#    Ian Romanick <idr@us.ibm.com>

import gl_XML, license
import sys, getopt, copy

def should_use_push(registers):
	for [reg, offset] in registers:
		if reg[1:4] == "xmm":
			return 0

	N = len(registers)
	return (N & 1) != 0


def local_size(registers):
	# The x86-64 ABI says "the value (%rsp - 8) is always a multiple of
	# 16 when control is transfered to the function entry point."  This
	# means that the local stack usage must be (16*N)+8 for some value
	# of N.  (16*N)+8 = (8*(2N))+8 = 8*(2N+1).  As long as N is odd, we
	# meet this requirement.

	N = (len(registers) | 1)
	return 8*N


def save_all_regs(registers):
	adjust_stack = 0
	if not should_use_push(registers):
		adjust_stack = local_size(registers)
		print '\tsubq\t$%u, %%rsp' % (adjust_stack)

	for [reg, stack_offset] in registers:
		save_reg( reg, stack_offset, adjust_stack )
	return


def restore_all_regs(registers):
	adjust_stack = 0
	if not should_use_push(registers):
		adjust_stack = local_size(registers)

	temp = copy.deepcopy(registers)
	while len(temp):
		[reg, stack_offset] = temp.pop()
		restore_reg(reg, stack_offset, adjust_stack)

	if adjust_stack:
		print '\taddq\t$%u, %%rsp' % (adjust_stack)
	return


def save_reg(reg, offset, use_move):
	if use_move:
		if offset == 0:
			print '\tmovq\t%s, (%%rsp)' % (reg)
		else:
			print '\tmovq\t%s, %u(%%rsp)' % (reg, offset)
	else:
		print '\tpushq\t%s' % (reg)

	return


def restore_reg(reg, offset, use_move):
	if use_move:
		if offset == 0:
			print '\tmovq\t(%%rsp), %s' % (reg)
		else:
			print '\tmovq\t%u(%%rsp), %s' % (offset, reg)
	else:
		print '\tpopq\t%s' % (reg)

	return


class PrintGenericStubs(gl_XML.gl_print_base):

	def __init__(self):
		gl_XML.gl_print_base.__init__(self)

		self.name = "gl_x86-64_asm.py (from Mesa)"
		self.license = license.bsd_license_template % ("(C) Copyright IBM Corporation 2005", "IBM")
		return


	def get_stack_size(self, f):
		size = 0
		for p in f.parameterIterator():
			size += p.get_stack_size()

		return size


	def printRealHeader(self):
		print "/* If we build with gcc's -fvisibility=hidden flag, we'll need to change"
		print " * the symbol visibility mode to 'default'."
		print ' */'
		print ''
		print '#include "assyntax.h"'
		print ''
		print '#if defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) >= 303'
		print '#  pragma GCC visibility push(default)'
		print '#  define HIDDEN(x) .hidden x'
		print '#else'
		print '#  define HIDDEN(x)'
		print '#endif'
		print ''
		print '# if defined(USE_MGL_NAMESPACE)'
		print '#  define GL_PREFIX(n) GLNAME(CONCAT(mgl,n))'
		print '# else'
		print '#  define GL_PREFIX(n) GLNAME(CONCAT(gl,n))'
		print '# endif'
		print ''
		print '#if defined(PTHREADS) || defined(USE_XTHREADS) || defined(SOLARIS_THREADS) || defined(WIN32_THREADS) || defined(BEOS_THREADS)'
		print '#  define THREADS'
		print '#endif'
		print ''
		print '\t.text'
		print ''
		print '#ifdef GLX_USE_TLS'
		print ''
		print '\t.globl _x86_64_get_get_dispatch; HIDDEN(_x86_64_get_get_dispatch)'
		print '_x86_64_get_get_dispatch:'
		print '\tlea\t_x86_64_get_dispatch(%rip), %rax'
		print '\tret'
		print ''
		print '\t.p2align\t4,,15'
		print '_x86_64_get_dispatch:'
		print '\tmovq\t_glapi_tls_Dispatch@GOTTPOFF(%rip), %rax'
		print '\tmovq\t%fs:(%rax), %rax'
		print '\tret'
		print '\t.size\t_x86_64_get_dispatch, .-_x86_64_get_dispatch'
		print ''
		print '#elif defined(PTHREADS)'
		print ''
		print '\t.extern\t_glapi_Dispatch'
		print '\t.extern\t_gl_DispatchTSD'
		print '\t.extern\tpthread_getspecific'
		print ''
		print '\t.p2align\t4,,15'
		print '_x86_64_get_dispatch:'
		print '\tmovq\t_gl_DispatchTSD(%rip), %rdi'
		print '\tjmp\tpthread_getspecific@PLT'
		print ''
		print '#elif defined(THREADS)'
		print ''
		print '\t.extern\t_glapi_get_dispatch'
		print ''
		print '#endif'
		print ''
		return


	def printRealFooter(self):
		print ''
		print '#if defined(GLX_USE_TLS) && defined(__linux__)'
		print '	.section ".note.ABI-tag", "a"'
		print '	.p2align 2'
		print '	.long	1f - 0f   /* name length */'
		print '	.long	3f - 2f   /* data length */'
		print '	.long	1         /* note length */'
		print '0:	.asciz "GNU"      /* vendor name */'
		print '1:	.p2align 2'
		print '2:	.long	0         /* note data: the ABI tag */'
		print '	.long	2,4,20    /* Minimum kernel version w/TLS */'
		print '3:	.p2align 2        /* pad out section */'
		print '#endif /* GLX_USE_TLS */'
		return


	def printFunction(self, f):
		
		# The x86-64 ABI divides function parameters into a couple
		# classes.  For the OpenGL interface, the only ones that are
		# relevent are INTEGER and SSE.  Basically, the first 8
		# GLfloat or GLdouble parameters are placed in %xmm0 - %xmm7,
		# the first 6 non-GLfloat / non-GLdouble parameters are placed
		# in registers listed in int_parameters.
		#
		# If more parameters than that are required, they are passed
		# on the stack.  Therefore, we just have to make sure that
		# %esp hasn't changed when we jump to the actual function.
		# Since we're jumping to the function (and not calling it), we
		# have to make sure of that anyway!

		int_parameters = ["%rdi", "%rsi", "%rdx", "%rcx", "%r8", "%r9"]

		int_class = 0
		sse_class = 0
		stack_offset = 0
		registers = []
		for p in f.parameterIterator():
			type_name = p.get_base_type_string()

			if p.is_pointer() or (type_name != "GLfloat" and type_name != "GLdouble"):
				if int_class < 6:
					registers.append( [int_parameters[int_class], stack_offset] )
					int_class += 1
					stack_offset += 8
			else:
				if sse_class < 8:
					registers.append( ["%%xmm%u" % (sse_class), stack_offset] )
					sse_class += 1
					stack_offset += 8

		if ((int_class & 1) == 0) and (sse_class == 0):
			registers.append( ["%rbp", 0] )


		print '\t.p2align\t4,,15'
		print '\t.globl\tGL_PREFIX(%s)' % (f.name)
		print '\t.type\tGL_PREFIX(%s), @function' % (f.name)
		print 'GL_PREFIX(%s):' % (f.name)
		print '#if defined(GLX_USE_TLS)'
		print '\tcall\t_x86_64_get_dispatch@PLT'
		print '\tmovq\t%u(%%rax), %%r11' % (f.offset * 8)
		print '\tjmp\t*%r11'
		print '#elif defined(PTHREADS)'
		
		save_all_regs(registers)
		print '\tcall\t_x86_64_get_dispatch@PLT'
		restore_all_regs(registers)

		if f.offset == 0:
			print '\tmovq\t(%rax), %r11'
		else:
			print '\tmovq\t%u(%%rax), %%r11' % (f.offset * 8)

		print '\tjmp\t*%r11'

		print '#else'
		print '\tmovq\t_glapi_Dispatch(%rip), %rax'
		print '\ttestq\t%rax, %rax'
		print '\tje\t1f'
		print '\tmovq\t%u(%%rax), %%r11' % (f.offset * 8)
		print '\tjmp\t*%r11'
		print '1:'

		save_all_regs(registers)
		print '\tcall\t_glapi_get_dispatch'
		restore_all_regs(registers)

		print '\tmovq\t%u(%%rax), %%r11' % (f.offset * 8)
		print '\tjmp\t*%r11'
		print '#endif /* defined(GLX_USE_TLS) */'

		print '\t.size\tGL_PREFIX(%s), .-GL_PREFIX(%s)' % (f.name, f.name)
		print ''
		return


	def printBody(self, api):
		for f in api.functionIterateByOffset():
			self.printFunction(f)


		for f in api.functionIterateByOffset():
			for n in f.entry_points:
				if n != f.name:
					print '\t.globl GL_PREFIX(%s) ; .set GL_PREFIX(%s), GL_PREFIX(%s)' % (n, n, f.name)

		return

def show_usage():
	print "Usage: %s [-f input_file_name] [-m output_mode]" % sys.argv[0]
	sys.exit(1)

if __name__ == '__main__':
	file_name = "gl_API.xml"
	mode = "generic"

	try:
		(args, trail) = getopt.getopt(sys.argv[1:], "m:f:")
	except Exception,e:
		show_usage()

	for (arg,val) in args:
		if arg == '-m':
			mode = val
		elif arg == "-f":
			file_name = val

	if mode == "generic":
		printer = PrintGenericStubs()
	else:
		print "ERROR: Invalid mode \"%s\" specified." % mode
		show_usage()

	api = gl_XML.parse_GL_API( file_name )

	printer.Print( api )
