arm.md

gcc库的原代码,对编程有很大帮助.

;;- Machine description for Advanced RISC Machines' ARM for GNU compiler
;;  Copyright (C) 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
;;  Contributed by Pieter `Tiggr' Schoenmakers ([e-mail])
;;             and Martin Simmons (@harleqn.co.uk).
;;  More major hacks by Richard Earnshaw ([e-mail])

;; This file is part of GNU CC.

;; GNU CC 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.

;; GNU CC 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 GNU CC; see the file COPYING.  If not, write to
;; the Free Software Foundation, 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;- See file "rtl.def" for documentation on define_insn, match_*, et. al.

;; There are patterns in this file to support XFmode arithmetic.
;; Unfortunately RISC iX doesn't work well with these so they are disabled.
;; (See arm.h)

;; UNSPEC Usage:
;; 0 `sin' operation: operand 0 is the result, operand 1 the parameter,
;;   the mode is MODE_FLOAT
;; 1 `cos' operation: operand 0 is the result, operand 1 the parameter,
;;   the mode is MODE_FLOAT
;; 2 `push multiple' operation: operand 0 is the first register.  Subsequent
;;   registers are in parallel (use...) expressions.

;; Attributes

; condition codes: this one is used by final_prescan_insn to speed up
; conditionalizing instructions.  It saves having to scan the rtl to see if
; it uses or alters the condition codes.

; USE means that the condition codes are used by the insn in the process of
; outputting code, this means (at present) that we can't use the insn in
; inlined branches

; SET means that the purpose of the insn is to set the condition codes in a
; well defined manner.

; CLOB means that the condition codes are altered in an undefined manner, if
; they are altered at all

; JUMP_CLOB is used when the conditions are not defined if a branch is taken,
; but are if the branch wasn't taken; the effect is to limit the branch
; elimination scanning.

; NOCOND means that the condition codes are neither altered nor affect the
; output of this insn

(define_attr "conds" "use,set,clob,jump_clob,nocond"
	(const_string "nocond"))

; CPU attribute is used to determine whether condition codes are clobbered
; by a call insn: on the arm6 they are if in 32-bit addressing mode; on the
; arm2 and arm3 the condition codes are restored by the return.

(define_attr "cpu" "arm2,arm3,arm6" (const (symbol_ref "arm_cpu_attr")))

; Floating Point Unit.  If we only have floating point emulation, then there
; is no point in scheduling the floating point insns.  (Well, for best
; performance we should try and group them together).

(define_attr "fpu" "fpa,fpe" (const (symbol_ref "arm_fpu_attr")))

; LENGTH of an instruction (in bytes)
(define_attr "length" "" (const_int 4))

; An assembler sequence may clobber the condition codes without us knowing
(define_asm_attributes
 [(set_attr "conds" "clob")
  (set_attr "length" "4")])

; TYPE attribute is used to detect floating point instructions which, if
; running on a co-processor can run in parallel with other, basic instructions
; If write-buffer scheduling is enabled then it can also be used in the
; scheduling of writes.

; Classification of each insn
; normal	any data instruction that doesn't hit memory or fp regs
; block		blockage insn, this blocks all functional units
; float		a floating point arithmetic operation (subject to expansion)
; fdivx		XFmode floating point division
; fdivd		DFmode floating point division
; fdivs		SFmode floating point division
; fmul		Floating point multiply
; ffmul		Fast floating point multiply
; farith	Floating point arithmetic (4 cycle)
; ffarith	Fast floating point arithmetic (2 cycle)
; float_em	a floating point arithmetic operation that is normally emulated
;		even on a machine with an fpa.
; f_load	a floating point load from memory
; f_store	a floating point store to memory
; f_mem_r	a transfer of a floating point register to a real reg via mem
; r_mem_f	the reverse of f_mem_r
; f_2_r		fast transfer float to arm (no memory needed)
; r_2_f		fast transfer arm to float
; call		a subroutine call
; load		any load from memory
; store1	store 1 word to memory from arm registers
; store2	store 2 words
; store3	store 3 words
; store4	store 4 words
;
(define_attr "type"
	"normal,block,float,fdivx,fdivd,fdivs,fmul,ffmul,farith,ffarith,float_em,f_load,f_store,f_mem_r,r_mem_f,f_2_r,r_2_f,call,load,store1,store2,store3,store4" 
	(const_string "normal"))

(define_attr "write_conflict" "no,yes"
  (if_then_else (eq_attr "type"
		 "block,float_em,f_load,f_store,f_mem_r,r_mem_f,call,load")
		(const_string "yes")
		(const_string "no")))

; The write buffer on some of the arm6 processors is hard to model exactly.
; There is room in the buffer for up to two addresses and up to eight words
; of memory, but the two needn't be split evenly.  When writing the two
; addresses are fully pipelined.  However, a read from memory that is not
; currently in the cache will block until the writes have completed.
; It is normally the case that FCLK and MCLK will be in the ratio 2:1, so
; writes will take 2 FCLK cycles per word, if FCLK and MCLK are asynchronous
; (they aren't allowed to be at present) then there is a startup cost of 1MCLK
; cycle to add as well.

;; (define_function_unit {name} {num-units} {n-users} {test}
;;                       {ready-delay} {issue-delay} [{conflict-list}])
(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "fdivx")) 71 69)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "fdivd")) 59 57)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "fdivs")) 31 29)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "fmul")) 9 7)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "ffmul")) 6 4)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "farith")) 4 2)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "ffarith")) 2 2)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "r_2_f")) 5 3)

(define_function_unit "fpa" 1 0 (and (eq_attr "fpu" "fpa")
				     (eq_attr "type" "f_2_r")) 1 2)

;; The fpa10 doesn't really have a memory read unit, but it can start to
;; speculatively execute the instruction in the pipeline, provided the data
;; is already loaded, so pretend reads have a delay of 2 (and that the
;; pipeline is infinite.

(define_function_unit "fpa_mem" 1 0 (and (eq_attr "fpu" "fpa")
					 (eq_attr "type" "f_load")) 3 1)

(define_function_unit "write_buf" 1 2 (eq_attr "type" "store1") 3 3
	[(eq_attr "write_conflict" "yes")])
(define_function_unit "write_buf" 1 2 (eq_attr "type" "store2") 5 5
	[(eq_attr "write_conflict" "yes")])
(define_function_unit "write_buf" 1 2 (eq_attr "type" "store3") 7 7
	[(eq_attr "write_conflict" "yes")])
(define_function_unit "write_buf" 1 2 (eq_attr "type" "store4") 9 9
	[(eq_attr "write_conflict" "yes")])
(define_function_unit "write_buf" 1 2 (eq_attr "type" "r_mem_f") 3 3
	[(eq_attr "write_conflict" "yes")])

;; Note: For DImode insns, there is normally no reason why operands should
;; not be in the same register, what we don't want is for something being
;; written to partially overlap something that is an input.

;; Addition insns.

(define_insn "adddi3"
  [(set (match_operand:DI 0 "s_register_operand" "=&r,&r")
	(plus:DI (match_operand:DI 1 "s_register_operand" "%0,0")
		 (match_operand:DI 2 "s_register_operand" "r,0")))
   (clobber (reg:CC 24))]
  ""
  "adds\\t%0, %1, %2\;adc\\t%R0, %R1, %R2"
[(set_attr "conds" "clob")
 (set_attr "length" "8")])

(define_insn ""
  [(set (match_operand:DI 0 "s_register_operand" "=&r,&r")
	(plus:DI (sign_extend:DI
		  (match_operand:SI 1 "s_register_operand" "r,r"))
		 (match_operand:DI 2 "s_register_operand" "r,0")))
   (clobber (reg:CC 24))]
  ""
  "adds\\t%0, %2, %1\;adc\\t%R0, %R2, %1, asr #31"
[(set_attr "conds" "clob")
 (set_attr "length" "8")])

(define_insn ""
  [(set (match_operand:DI 0 "s_register_operand" "=&r,&r")
	(plus:DI (zero_extend:DI
		  (match_operand:SI 1 "s_register_operand" "r,r"))
		 (match_operand:DI 2 "s_register_operand" "r,0")))
   (clobber (reg:CC 24))]
  ""
  "adds\\t%0, %2, %1\;adc\\t%R0, %R2, #0"
[(set_attr "conds" "clob")
 (set_attr "length" "8")])

(define_expand "addsi3"
  [(set (match_operand:SI 0 "s_register_operand" "")
	(plus:SI (match_operand:SI 1 "s_register_operand" "")
		 (match_operand:SI 2 "reg_or_int_operand" "")))]
  ""
  "
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      arm_split_constant (PLUS, SImode, INTVAL (operands[2]), operands[0],
			  operands[1],
			  (reload_in_progress || reload_completed ? 0
			   : preserve_subexpressions_p ()));
      DONE;
    }
")

(define_split
  [(set (match_operand:SI 0 "s_register_operand" "")
	(plus:SI (match_operand:SI 1 "s_register_operand" "")
		 (match_operand:SI 2 "const_int_operand" "")))]
  "! (const_ok_for_arm (INTVAL (operands[2]))
      || const_ok_for_arm (-INTVAL (operands[2])))"
  [(clobber (const_int 0))]
  "
  arm_split_constant (PLUS, SImode, INTVAL (operands[2]), operands[0],
		      operands[1], 0);
  DONE;
")

(define_insn ""
  [(set (match_operand:SI 0 "s_register_operand" "=r,r,r")
	(plus:SI (match_operand:SI 1 "s_register_operand" "r,r,r")
		 (match_operand:SI 2 "reg_or_int_operand" "rI,L,?n")))]
  ""
  "@
   add%?\\t%0, %1, %2
   sub%?\\t%0, %1, #%n2
   #"
[(set_attr "length" "4,4,16")])

(define_insn ""
  [(set (reg:CC_NOOV 24)
	(compare:CC_NOOV
	 (plus:SI (match_operand:SI 1 "s_register_operand" "r,r")
		  (match_operand:SI 2 "arm_add_operand" "rI,L"))
	 (const_int 0)))
   (set (match_operand:SI 0 "s_register_operand" "=r,r")
	(plus:SI (match_dup 1) (match_dup 2)))]
  ""
  "@
   add%?s\\t%0, %1, %2
   sub%?s\\t%0, %1, #%n2"
[(set_attr "conds" "set")])

(define_insn ""
  [(set (reg:CC 24)
	(compare:CC (match_operand:SI 1 "s_register_operand" "r,r")
		    (neg:SI (match_operand:SI 2 "arm_add_operand" "rI,L"))))
   (set (match_operand:SI 0 "s_register_operand" "=r,r")
	(plus:SI (match_dup 1) (match_dup 2)))]
  ""
  "@
   add%?s\\t%0, %1, %2
   sub%?s\\t%0, %1, #%n2"
[(set_attr "conds" "set")])

(define_insn "incscc"
  [(set (match_operand:SI 0 "s_register_operand" "=r,r")
        (plus:SI (match_operator:SI 2 "comparison_operator"
                    [(reg 24) (const_int 0)])
                 (match_operand:SI 1 "s_register_operand" "0,?r")))]
  ""
  "@
  add%d2\\t%0, %1, #1
  mov%D2\\t%0, %1\;add%d2\\t%0, %1, #1"
[(set_attr "conds" "use")
 (set_attr "length" "4,8")])

; If a constant is too big to fit in a single instruction then the constant
; will be pre-loaded into a register taking at least two insns, we might be
; able to merge it with an add, but it depends on the exact value.

(define_split
  [(set (match_operand:SI 0 "s_register_operand" "=r")
	(plus:SI (match_operand:SI 1 "s_register_operand" "r")
		 (match_operand:SI 2 "immediate_operand" "n")))]
  "!(const_ok_for_arm (INTVAL (operands[2]))
     || const_ok_for_arm (-INTVAL (operands[2])))"
  [(set (match_dup 0) (plus:SI (match_dup 1) (match_dup 2)))
   (set (match_dup 0) (plus:SI (match_dup 0) (match_dup 3)))]
  "
{
  unsigned int val = (unsigned) INTVAL (operands[2]);
  int i;
  unsigned int temp;

  /* this code is similar to the approach followed in movsi, but it must
     generate exactly two insns */

  for (i = 30; i >= 0; i -= 2)
    {
      if (val & (3 << i))
	{
	  i -= 6;
	  if (i < 0) i = 0;
	  if (const_ok_for_arm (temp = (val & ~(255 << i))))
	    {
	      val &= 255 << i;
	      break;
	    }
	  /* we might be able to do this as (larger number - small number) */
	  temp = ((val >> i) & 255) + 1;
	  if (temp > 255 && i < 24)
	    {
	      i += 2;
	      temp = ((val >> i) & 255) + 1;
	    }
	  if (const_ok_for_arm ((temp << i) - val))
	    {
	      i = temp << i;
	      temp = (unsigned) - (int) (i - val);
	      val = i;
	      break;
	    }
	  FAIL;
	}
    }
  /* if we got here, we have found a way of doing it in two instructions.
     the two constants are in val and temp */
  operands[2] = GEN_INT ((int)val);
  operands[3] = GEN_INT ((int)temp);
}
")

(define_insn "addsf3"
  [(set (match_operand:SF 0 "s_register_operand" "=f,f")
	(plus:SF (match_operand:SF 1 "s_register_operand" "f,f")
		 (match_operand:SF 2 "fpu_add_operand" "fG,H")))]
  "TARGET_HARD_FLOAT"
  "@
   adf%?s\\t%0, %1, %2
   suf%?s\\t%0, %1, #%N2"
[(set_attr "type" "farith")])

(define_insn "adddf3"
  [(set (match_operand:DF 0 "s_register_operand" "=f,f")
	(plus:DF (match_operand:DF 1 "s_register_operand" "f,f")
		 (match_operand:DF 2 "fpu_add_operand" "fG,H")))]
  "TARGET_HARD_FLOAT"
  "@
   adf%?d\\t%0, %1, %2
   suf%?d\\t%0, %1, #%N2"
[(set_attr "type" "farith")])

(define_insn ""
  [(set (match_operand:DF 0 "s_register_operand" "=f,f")
	(plus:DF (float_extend:DF
		  (match_operand:SF 1 "s_register_operand" "f,f"))
		 (match_operand:DF 2 "fpu_add_operand" "fG,H")))]
  "TARGET_HARD_FLOAT"
  "@
   adf%?d\\t%0, %1, %2
   suf%?d\\t%0, %1, #%N2"
[(set_attr "type" "farith")])

(define_insn ""
  [(set (match_operand:DF 0 "s_register_operand" "=f")
	(plus:DF (match_operand:DF 1 "s_register_operand" "f")
		 (float_extend:DF
		  (match_operand:SF 2 "s_register_operand" "f"))))]
  "TARGET_HARD_FLOAT"
  "adf%?d\\t%0, %1, %2"
[(set_attr "type" "farith")])

(define_insn ""
  [(set (match_operand:DF 0 "s_register_operand" "=f")
	(plus:DF (float_extend:DF 
		  (match_operand:SF 1 "s_register_operand" "f"))
		 (float_extend:DF
		  (match_operand:SF 2 "s_register_operand" "f"))))]
  "TARGET_HARD_FLOAT"
  "adf%?d\\t%0, %1, %2"
[(set_attr "type" "farith")])

(define_insn "addxf3"
  [(set (match_operand:XF 0 "s_register_operand" "=f,f")
	(plus:XF (match_operand:XF 1 "s_register_operand" "f,f")
		 (match_operand:XF 2 "fpu_add_operand" "fG,H")))]
  "ENABLE_XF_PATTERNS && TARGET_HARD_FLOAT"
  "@
   adf%?e\\t%0, %1, %2
   suf%?e\\t%0, %1, #%N2"
[(set_attr "type" "farith")])

(define_insn "subdi3"
  [(set (match_operand:DI 0 "s_register_operand" "=&r,&r,&r")
	(minus:DI (match_operand:DI 1 "s_register_operand" "0,r,0")
		  (match_operand:DI 2 "s_register_operand" "r,0,0")))
   (clobber (reg:CC 24))]
  ""
  "subs\\t%0, %1, %2\;sbc\\t%R0, %R1, %R2"
[(set_attr "conds" "clob")
 (set_attr "length" "8")])