xtensa.md

gcc-you can use this code to learn something about gcc, and inquire further into linux,

;; GCC machine description for Tensilica's Xtensa architecture.
;; Copyright (C) 2001 Free Software Foundation, Inc.
;; Contributed by Bob Wilson ([e-mail]) at Tensilica.

;; This file is part of GCC.

;; GCC 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 2, or (at your option)
;; any later version.

;; GCC 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.

;; You should have received a copy of the GNU General Public License
;; along with GCC; see the file COPYING.  If not, write to the Free
;; Software Foundation, 59 Temple Place - Suite 330, Boston, MA
;; 02111-1307, USA.

;;
;; ....................
;;
;;	CONSTANTS
;;
;; ....................
;;

(define_constants [
  (A0_REG		0)
  (A7_REG		7)

  (UNSPEC_NSAU		1)
  (UNSPEC_NOP		2)
  (UNSPEC_PLT		3)
  (UNSPEC_RET_ADDR	4)
  (UNSPECV_SET_FP	1)
])

;;
;; ....................
;;
;;	ATTRIBUTES
;;
;; ....................
;;

(define_attr "type"
  "unknown,jump,call,load,store,move,arith,multi,nop,farith,fmadd,fdiv,fsqrt,fconv,fload,fstore,mul16,mul32,div32,mac16,rsr,wsr"
  (const_string "unknown"))

(define_attr "mode"
  "unknown,none,QI,HI,SI,DI,SF,DF,BL"
  (const_string "unknown"))

(define_attr "length" "" (const_int 1))

;; Describe a user's asm statement.
(define_asm_attributes
  [(set_attr "type" "multi")])


;;
;; ....................
;;
;;	FUNCTIONAL UNITS
;;
;; ....................
;;

(define_function_unit "memory" 1 0 (eq_attr "type" "load,fload") 2 0)

(define_function_unit "sreg" 1 1 (eq_attr "type" "rsr") 2 0)

(define_function_unit "mul16" 1 0 (eq_attr "type" "mul16") 2 0)

(define_function_unit "mul32" 1 0 (eq_attr "type" "mul32") 2 0)

(define_function_unit "fpmadd" 1 0 (eq_attr "type" "fmadd") 4 0)

(define_function_unit "fpconv" 1 0 (eq_attr "type" "fconv") 2 0)


;;
;;  ....................
;;
;;	ADDITION
;;
;;  ....................
;;

(define_expand "adddi3"
  [(set (match_operand:DI 0 "register_operand" "")
	(plus:DI (match_operand:DI 1 "register_operand" "")
		 (match_operand:DI 2 "register_operand" "")))]
  ""
  "
{
  rtx srclo;
  rtx dstlo = gen_lowpart (SImode, operands[0]);
  rtx src1lo = gen_lowpart (SImode, operands[1]);
  rtx src2lo = gen_lowpart (SImode, operands[2]);

  rtx dsthi = gen_highpart (SImode, operands[0]);
  rtx src1hi = gen_highpart (SImode, operands[1]);
  rtx src2hi = gen_highpart (SImode, operands[2]);

  /* Either source can be used for overflow checking, as long as it's
     not clobbered by the first addition.  */
  if (!rtx_equal_p (dstlo, src1lo))
    srclo = src1lo;
  else if (!rtx_equal_p (dstlo, src2lo))
    srclo = src2lo;
  else
    {
      srclo = gen_reg_rtx (SImode);
      emit_move_insn (srclo, src1lo);
    }

  emit_insn (gen_addsi3 (dstlo, src1lo, src2lo));
  emit_insn (gen_addsi3 (dsthi, src1hi, src2hi));
  emit_insn (gen_adddi_carry (dsthi, dstlo, srclo));
  DONE;
}")

;; Represent the add-carry operation as an atomic operation instead of
;; expanding it to a conditional branch.  Otherwise, the edge
;; profiling code breaks because inserting the count increment code
;; causes a new jump insn to be added.

(define_insn "adddi_carry"
  [(set (match_operand:SI 0 "register_operand" "+a")
	(plus:SI (ltu:SI (match_operand:SI 1 "register_operand" "r")
			 (match_operand:SI 2 "register_operand" "r"))
		 (match_dup 0)))]
  ""
  "bgeu\\t%1, %2, 0f\;addi\\t%0, %0, 1\;0:"
  [(set_attr "type"	"multi")
   (set_attr "mode"	"SI")
   (set_attr "length"	"6")])

(define_insn "addsi3"
  [(set (match_operand:SI 0 "register_operand" "=D,D,a,a,a")
	(plus:SI (match_operand:SI 1 "register_operand" "%d,d,r,r,r")
		 (match_operand:SI 2 "add_operand" "d,O,r,J,N")))]
  ""
  "@
   add.n\\t%0, %1, %2
   addi.n\\t%0, %1, %d2
   add\\t%0, %1, %2
   addi\\t%0, %1, %d2
   addmi\\t%0, %1, %x2"
  [(set_attr "type"	"arith,arith,arith,arith,arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"2,2,3,3,3")])

(define_insn "*addx2"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(plus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
			  (const_int 2))
		 (match_operand:SI 2 "register_operand" "r")))]
  ""
  "addx2\\t%0, %1, %2"
  [(set_attr "type"	"arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "*addx4"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(plus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
			  (const_int 4))
		 (match_operand:SI 2 "register_operand" "r")))]
  ""
  "addx4\\t%0, %1, %2"
  [(set_attr "type"	"arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "*addx8"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(plus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
			  (const_int 8))
		 (match_operand:SI 2 "register_operand" "r")))]
  ""
  "addx8\\t%0, %1, %2"
  [(set_attr "type"	"arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "addsf3"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(plus:SF (match_operand:SF 1 "register_operand" "%f")
		 (match_operand:SF 2 "register_operand" "f")))]
  "TARGET_HARD_FLOAT"
  "add.s\\t%0, %1, %2"
  [(set_attr "type"	"fmadd")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])


;;
;;  ....................
;;
;;	SUBTRACTION
;;
;;  ....................
;;

(define_expand "subdi3"
  [(set (match_operand:DI 0 "register_operand" "")
	(minus:DI (match_operand:DI 1 "register_operand" "")
		  (match_operand:DI 2 "register_operand" "")))]
  ""
  "
{
  rtx dstlo = gen_lowpart (SImode, operands[0]);
  rtx src1lo = gen_lowpart (SImode, operands[1]);
  rtx src2lo = gen_lowpart (SImode, operands[2]);

  rtx dsthi = gen_highpart (SImode, operands[0]);
  rtx src1hi = gen_highpart (SImode, operands[1]);
  rtx src2hi = gen_highpart (SImode, operands[2]);

  emit_insn (gen_subsi3 (dsthi, src1hi, src2hi));
  emit_insn (gen_subdi_carry (dsthi, src1lo, src2lo));
  emit_insn (gen_subsi3 (dstlo, src1lo, src2lo));
  DONE;
}")

(define_insn "subdi_carry"
  [(set (match_operand:SI 0 "register_operand" "+a")
	(minus:SI (match_dup 0)
		  (ltu:SI (match_operand:SI 1 "register_operand" "r")
			  (match_operand:SI 2 "register_operand" "r"))))]
  ""
  "bgeu\\t%1, %2, 0f\;addi\\t%0, %0, -1\;0:"
  [(set_attr "type"	"multi")
   (set_attr "mode"	"SI")
   (set_attr "length"	"6")])

(define_insn "subsi3"
  [(set (match_operand:SI 0 "register_operand" "=a")
        (minus:SI (match_operand:SI 1 "register_operand" "r")
		  (match_operand:SI 2 "register_operand" "r")))]
  ""
  "sub\\t%0, %1, %2"
  [(set_attr "type"	"arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "*subx2"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(minus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
			   (const_int 2))
		  (match_operand:SI 2 "register_operand" "r")))]
  ""
  "subx2\\t%0, %1, %2"
  [(set_attr "type"	"arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "*subx4"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(minus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
			   (const_int 4))
		  (match_operand:SI 2 "register_operand" "r")))]
  ""
  "subx4\\t%0, %1, %2"
  [(set_attr "type"	"arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "*subx8"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(minus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
			   (const_int 8))
		  (match_operand:SI 2 "register_operand" "r")))]
  ""
  "subx8\\t%0, %1, %2"
  [(set_attr "type"	"arith")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "subsf3"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(minus:SF (match_operand:SF 1 "register_operand" "f")
		  (match_operand:SF 2 "register_operand" "f")))]
  "TARGET_HARD_FLOAT"
  "sub.s\\t%0, %1, %2"
  [(set_attr "type"	"fmadd")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])


;;
;;  ....................
;;
;;	MULTIPLICATION
;;
;;  ....................
;;

(define_insn "mulsi3"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(mult:SI (match_operand:SI 1 "register_operand" "%r")
		 (match_operand:SI 2 "register_operand" "r")))]
  "TARGET_MUL32"
  "mull\\t%0, %1, %2"
  [(set_attr "type"	"mul32")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "mulhisi3"
  [(set (match_operand:SI 0 "register_operand" "=C,A")
	(mult:SI (sign_extend:SI
		  (match_operand:HI 1 "register_operand" "%r,r"))
		 (sign_extend:SI
		  (match_operand:HI 2 "register_operand" "r,r"))))]
  "TARGET_MUL16 || TARGET_MAC16"
  "@
   mul16s\\t%0, %1, %2
   mul.aa.ll\\t%1, %2"
  [(set_attr "type"	"mul16,mac16")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3,3")])

(define_insn "umulhisi3"
  [(set (match_operand:SI 0 "register_operand" "=C,A")
	(mult:SI (zero_extend:SI
		  (match_operand:HI 1 "register_operand" "%r,r"))
		 (zero_extend:SI
		  (match_operand:HI 2 "register_operand" "r,r"))))]
  "TARGET_MUL16 || TARGET_MAC16"
  "@
   mul16u\\t%0, %1, %2
   umul.aa.ll\\t%1, %2"
  [(set_attr "type"	"mul16,mac16")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3,3")])

(define_insn "muladdhisi"
  [(set (match_operand:SI 0 "register_operand" "=A")
	(plus:SI (mult:SI (sign_extend:SI
			   (match_operand:HI 1 "register_operand" "%r"))
			  (sign_extend:SI
			   (match_operand:HI 2 "register_operand" "r")))
		 (match_operand:SI 3 "register_operand" "0")))]
  "TARGET_MAC16"
  "mula.aa.ll\\t%1, %2"
  [(set_attr "type"	"mac16")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "mulsubhisi"
  [(set (match_operand:SI 0 "register_operand" "=A")
	(minus:SI (match_operand:SI 1 "register_operand" "0")
		  (mult:SI (sign_extend:SI
			    (match_operand:HI 2 "register_operand" "%r"))
			   (sign_extend:SI
			    (match_operand:HI 3 "register_operand" "r")))))]
  "TARGET_MAC16"
  "muls.aa.ll\\t%2, %3"
  [(set_attr "type"	"mac16")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "mulsf3"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(mult:SF (match_operand:SF 1 "register_operand" "%f")
		 (match_operand:SF 2 "register_operand" "f")))]
  "TARGET_HARD_FLOAT"
  "mul.s\\t%0, %1, %2"
  [(set_attr "type"	"fmadd")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])

(define_insn "muladdsf3"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(plus:SF (mult:SF (match_operand:SF 1 "register_operand" "%f")
			  (match_operand:SF 2 "register_operand" "f"))
		 (match_operand:SF 3 "register_operand" "0")))]
  "TARGET_HARD_FLOAT && !TARGET_NO_FUSED_MADD"
  "madd.s\\t%0, %1, %2"
  [(set_attr "type"	"fmadd")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])

(define_insn "mulsubsf3"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(minus:SF (match_operand:SF 1 "register_operand" "0")
		  (mult:SF (match_operand:SF 2 "register_operand" "%f")
			   (match_operand:SF 3 "register_operand" "f"))))]
  "TARGET_HARD_FLOAT && !TARGET_NO_FUSED_MADD"
  "msub.s\\t%0, %2, %3"
  [(set_attr "type"	"fmadd")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])


;;
;;  ....................
;;
;;	DIVISION
;;
;;  ....................
;;

(define_insn "divsi3"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(div:SI (match_operand:SI 1 "register_operand" "r")
		(match_operand:SI 2 "register_operand" "r")))]
  "TARGET_DIV32"
  "quos\\t%0, %1, %2"
  [(set_attr "type"	"div32")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "udivsi3"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(udiv:SI (match_operand:SI 1 "register_operand" "r")
		 (match_operand:SI 2 "register_operand" "r")))]
  "TARGET_DIV32"
  "quou\\t%0, %1, %2"
  [(set_attr "type"	"div32")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "divsf3"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(div:SF (match_operand:SF 1 "register_operand" "f")
		(match_operand:SF 2 "register_operand" "f")))]
  "TARGET_HARD_FLOAT_DIV"
  "div.s\\t%0, %1, %2"
  [(set_attr "type"	"fdiv")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])

(define_insn "*recipsf2"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(div:SF (match_operand:SF 1 "const_float_1_operand" "")
		(match_operand:SF 2 "register_operand" "f")))]
  "TARGET_HARD_FLOAT_RECIP && flag_unsafe_math_optimizations"
  "recip.s\\t%0, %2"
  [(set_attr "type"	"fdiv")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])


;;
;;  ....................
;;
;;	REMAINDER
;;
;;  ....................
;;

(define_insn "modsi3"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(mod:SI (match_operand:SI 1 "register_operand" "r")
		(match_operand:SI 2 "register_operand" "r")))]
  "TARGET_DIV32"
  "rems\\t%0, %1, %2"
  [(set_attr "type"	"div32")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])

(define_insn "umodsi3"
  [(set (match_operand:SI 0 "register_operand" "=a")
	(umod:SI (match_operand:SI 1 "register_operand" "r")
		 (match_operand:SI 2 "register_operand" "r")))]
  "TARGET_DIV32"
  "remu\\t%0, %1, %2"
  [(set_attr "type"	"div32")
   (set_attr "mode"	"SI")
   (set_attr "length"	"3")])


;;
;;  ....................
;;
;;	SQUARE ROOT
;;
;;  ....................
;;

(define_insn "sqrtsf2"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(sqrt:SF (match_operand:SF 1 "register_operand" "f")))]
  "TARGET_HARD_FLOAT_SQRT"
  "sqrt.s\\t%0, %1"
  [(set_attr "type"	"fsqrt")
   (set_attr "mode"	"SF")
   (set_attr "length"	"3")])

(define_insn "*rsqrtsf2"
  [(set (match_operand:SF 0 "register_operand" "=f")
	(div:SF (match_operand:SF 1 "const_float_1_operand" "")
		(sqrt:SF (match_operand:SF 2 "register_operand" "f"))))]
  "TARGET_HARD_FLOAT_RSQRT && flag_unsafe_math_optimizations"