--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/config/picochip/libgccExtras/divmod15.asm	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,263 @@
+// picoChip ASM file
+//
+//   Support for 16-bit unsigned division/modulus.
+//
+//   Copyright (C) 2003, 2004, 2005, 2008, 2009  Free Software Foundation, Inc.
+//   Contributed by picoChip Designs Ltd.
+//   Maintained by Daniel Towner (daniel.towner@picochip.com)
+//
+//   This file is free software; you can redistribute it and/or modify it
+//   under the terms of the GNU General Public License as published by the
+//   Free Software Foundation; either version 3, or (at your option) any
+//   later version.
+//
+//   This file is distributed in the hope that it will be useful, but
+//   WITHOUT ANY WARRANTY; without even the implied warranty of
+//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//   General Public License for more details.
+//
+//   Under Section 7 of GPL version 3, you are granted additional
+//   permissions described in the GCC Runtime Library Exception, version
+//   3.1, as published by the Free Software Foundation.
+//   
+//   You should have received a copy of the GNU General Public License and
+//   a copy of the GCC Runtime Library Exception along with this program;
+//   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+//   <http://www.gnu.org/licenses/>.
+	
+.section .text
+
+.global __divmod15
+__divmod15:
+_picoMark_FUNCTION_BEGIN=
+	
+// picoChip Function Prologue : &__divmod15 = 0 bytes
+
+__divmod15:	
+
+	// The picoChip instruction set has a divstep instruction which
+	// is used to perform one iteration of a binary division algorithm.
+	// The instruction allows 16-bit signed division to be implemented.
+	// It does not directly allow 16-bit unsigned division to be
+	// implemented. Thus, this function pulls out the common division
+	// iteration for 15-bits unsigned, and then special wrappers
+	// provide the logic to change this into a 16-bit signed or
+	// unsigned division, as appropriate. This allows the two
+	// versions of division to share a common implementation, reducing
+	// code size when the two are used together. It also reduces
+	// the maintenance overhead.
+
+	// Input:
+	//	r0 - dividend
+	//	r1 - divisor
+	// Output:
+	//	r0 - quotient
+	//	r1 - remainder
+	// R5 is unused
+	
+	// Check for special cases. The emphasis is on detecting these as
+	// quickly as possible, so that the main division can be started. If 
+	// the user requests division by one, division by self, and so on
+	// then they will just have to accept that this won't be particularly
+	// quick (relatively), whereas a real division (e.g., dividing a 
+	// large value by a small value) will run as fast as possible
+	// (i.e., special case detection should not slow down the common case)
+	//
+	// Special cases to consider:
+	//
+	//	Division by zero.
+	//	Division of zero.
+	//	Inputs are equal
+	//	Divisor is bigger than dividend
+	//	Division by power of two (can be shifted instead).
+	//	Division by 1 (special case of power of two division)
+	//
+	// Division/modulus by zero is undefined (ISO C:6.5.5), so
+	// don't bother handling this special case.
+	//
+	// The special cases of division by a power of 2 are ignored, since 
+	// they cause the general case to slow down. Omitting these
+	// special cases also reduces code size considerably.
+
+	// Handle divisor >= dividend separately. Note that this also handles 
+	// the case where the dividend is zero.	Note that the flags must be
+	// preserved, since they are also used at the branch destination.
+	sub.0 r1,r0,r15
+	sbc r0,r2 \ bge divisorGeDividend
+=->	sbc r1,r4
+	
+	// Compute the shift count. The amount by which the divisor
+	// must be shifted left to be aligned with the dividend.	
+	sub.0 r4,r2,r3
+		
+	// Align the divisor to the dividend. Execute a divstep (since at 
+	// least one will always be executed). Skip the remaining loop
+	// if the shift count is zero.
+	lsl.0 r1,r3,r1 \ beq skipLoop
+=->	divstep r0,r1 \ add.1 r3,1,r2
+
+	// Execute the divstep loop until temp is 0. This assumes that the
+	// loop count is at least one.
+	sub.0 r3,1,r4
+divLoop:	
+	divstep r0,r1 \ bne divLoop
+=->	sub.0 r4,1,r4
+
+skipLoop:
+				
+	// The top bits of the result are the remainder. The bottom
+	// bits are the quotient.
+	lsr.0 r0,r2,r1 \ sub.1 16,r2,r4
+	jr (lr ) \ lsl.0 r0,r4,r0
+=->	lsr.0 r0,r4,r0
+
+// Special case.
+
+divisorGeDividend:	
+	// The divisor is greater than or equal to the dividend. The flags
+	// indicate which of these alternatives it is. The COPYNE can be used 
+	// to set the result appropriately, without introducing any more
+	// branches.
+	copy.0 r0,r1 \ copy.1 0,r0
+	jr (lr) \ copyeq r0,r1
+=->	copyeq 1,r0
+
+_picoMark_FUNCTION_END=
+// picoChip Function Epilogue : __divmod15
+
+	
+//============================================================================
+// All DWARF information between this marker, and the END OF DWARF
+// marker should be included in the source file. Search for
+// FUNCTION_STACK_SIZE_GOES_HERE and FUNCTION NAME GOES HERE, and
+// provide the relevent information. Add markers called
+// _picoMark_FUNCTION_BEGIN and _picoMark_FUNCTION_END around the
+// function in question.
+//============================================================================
+
+//============================================================================
+// Frame information. 
+//============================================================================
+
+.section .debug_frame
+_picoMark_DebugFrame=
+
+// Common CIE header.
+.unalignedInitLong _picoMark_CieEnd-_picoMark_CieBegin
+_picoMark_CieBegin=
+.unalignedInitLong 0xffffffff
+.initByte 0x1	// CIE Version
+.ascii 16#0#	// CIE Augmentation
+.uleb128 0x1	// CIE Code Alignment Factor
+.sleb128 2	// CIE Data Alignment Factor
+.initByte 0xc	// CIE RA Column
+.initByte 0xc	// DW_CFA_def_cfa
+.uleb128 0xd
+.uleb128 0x0
+.align 2
+_picoMark_CieEnd=
+
+// FDE 
+_picoMark_LSFDE0I900821033007563=
+.unalignedInitLong _picoMark_FdeEnd-_picoMark_FdeBegin
+_picoMark_FdeBegin=
+.unalignedInitLong _picoMark_DebugFrame	// FDE CIE offset
+.unalignedInitWord _picoMark_FUNCTION_BEGIN	// FDE initial location
+.unalignedInitWord _picoMark_FUNCTION_END-_picoMark_FUNCTION_BEGIN
+.initByte 0xe	// DW_CFA_def_cfa_offset
+.uleb128 0x0	// <-- FUNCTION_STACK_SIZE_GOES_HERE
+.initByte 0x4	// DW_CFA_advance_loc4
+.unalignedInitLong _picoMark_FUNCTION_END-_picoMark_FUNCTION_BEGIN
+.initByte 0xe	// DW_CFA_def_cfa_offset
+.uleb128 0x0
+.align 2
+_picoMark_FdeEnd=
+
+//============================================================================
+// Abbrevation information.
+//============================================================================
+
+.section .debug_abbrev
+_picoMark_ABBREVIATIONS=
+
+.section .debug_abbrev
+	.uleb128 0x1	// (abbrev code)
+	.uleb128 0x11	// (TAG: DW_TAG_compile_unit)
+	.initByte 0x1	// DW_children_yes
+	.uleb128 0x10	// (DW_AT_stmt_list)
+	.uleb128 0x6	// (DW_FORM_data4)
+	.uleb128 0x12	// (DW_AT_high_pc)
+	.uleb128 0x1	// (DW_FORM_addr)
+	.uleb128 0x11	// (DW_AT_low_pc)
+	.uleb128 0x1	// (DW_FORM_addr)
+	.uleb128 0x25	// (DW_AT_producer)
+	.uleb128 0x8	// (DW_FORM_string)
+	.uleb128 0x13	// (DW_AT_language)
+	.uleb128 0x5	// (DW_FORM_data2)
+	.uleb128 0x3	// (DW_AT_name)
+	.uleb128 0x8	// (DW_FORM_string)
+.initByte 0x0
+.initByte 0x0
+
+	.uleb128 0x2	;# (abbrev code)
+	.uleb128 0x2e	;# (TAG: DW_TAG_subprogram)
+.initByte 0x0	;# DW_children_no
+	.uleb128 0x3	;# (DW_AT_name)
+	.uleb128 0x8	;# (DW_FORM_string)
+	.uleb128 0x11	;# (DW_AT_low_pc)
+	.uleb128 0x1	;# (DW_FORM_addr)
+	.uleb128 0x12	;# (DW_AT_high_pc)
+	.uleb128 0x1	;# (DW_FORM_addr)
+.initByte 0x0
+.initByte 0x0
+
+.initByte 0x0
+
+//============================================================================
+// Line information. DwarfLib requires this to be present, but it can
+// be empty.
+//============================================================================
+
+.section .debug_line
+_picoMark_LINES=
+
+//============================================================================
+// Debug Information
+//============================================================================
+.section .debug_info
+
+//Fixed header.
+.unalignedInitLong _picoMark_DEBUG_INFO_END-_picoMark_DEBUG_INFO_BEGIN
+_picoMark_DEBUG_INFO_BEGIN=
+.unalignedInitWord 0x2
+.unalignedInitLong _picoMark_ABBREVIATIONS
+.initByte 0x2
+
+// Compile unit information.
+.uleb128 0x1	// (DIE 0xb) DW_TAG_compile_unit)
+.unalignedInitLong _picoMark_LINES
+.unalignedInitWord _picoMark_FUNCTION_END
+.unalignedInitWord _picoMark_FUNCTION_BEGIN
+// Producer is `picoChip'
+.ascii 16#70# 16#69# 16#63# 16#6f# 16#43# 16#68# 16#69# 16#70# 16#00#
+.unalignedInitWord 0xcafe // ASM language
+.ascii 16#0# // Name. DwarfLib expects this to be present.
+
+.uleb128 0x2	;# (DIE DW_TAG_subprogram)
+
+// FUNCTION NAME GOES HERE. Use `echo name | od -t x1' to get the hex. Each hex
+// digit is specified using the format 16#XX#
+.ascii 16#5f# 16#64# 16#69# 16#76# 16#6d# 16#6f# 16#64# 16#31# 16#35# 16#0# // Function name `_divmod15'
+.unalignedInitWord _picoMark_FUNCTION_BEGIN	// DW_AT_low_pc
+.unalignedInitWord _picoMark_FUNCTION_END	// DW_AT_high_pc
+
+.initByte 0x0	// end of compile unit children.
+
+_picoMark_DEBUG_INFO_END=
+
+//============================================================================
+// END OF DWARF
+//============================================================================
+
+.section .endFile
+// End of picoChip ASM file