m32r.md

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

  operands[6] = operand_subword (operands[0], (WORDS_BIG_ENDIAN == 0), 0, DImode);
  operands[7] = operand_subword (operands[2], (WORDS_BIG_ENDIAN == 0), 0, DImode);
}")

(define_insn "*sub_carry"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(minus:SI (match_operand:SI 1 "register_operand" "%0")
		  (minus:SI (match_operand:SI 2 "register_operand" "r")
			    (reg:SI 17))))
   (set (reg:SI 17)
	(unspec [(const_int 0)] 3))]
  ""
  "subx %0,%2"
  [(set_attr "type" "int2")
   (set_attr "length" "2")])

; Multiply/Divide instructions.

(define_insn "mulhisi3"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(mult:SI (sign_extend:SI (match_operand:HI 1 "register_operand" "r"))
		 (sign_extend:SI (match_operand:HI 2 "register_operand" "r"))))]
  ""
  "mullo %1,%2\;mvfacmi %0"
  [(set_attr "type" "multi")
   (set_attr "length" "4")])

(define_insn "mulsi3"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(mult:SI (match_operand:SI 1 "register_operand" "%0")
		 (match_operand:SI 2 "register_operand" "r")))]
  ""
  "mul %0,%2"
  [(set_attr "type" "mul2")
   (set_attr "length" "2")])

(define_insn "divsi3"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(div:SI (match_operand:SI 1 "register_operand" "0")
		(match_operand:SI 2 "register_operand" "r")))]
  ""
  "div %0,%2"
  [(set_attr "type" "div4")
   (set_attr "length" "4")])

(define_insn "udivsi3"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(udiv:SI (match_operand:SI 1 "register_operand" "0")
		 (match_operand:SI 2 "register_operand" "r")))]
  ""
  "divu %0,%2"
  [(set_attr "type" "div4")
   (set_attr "length" "4")])

(define_insn "modsi3"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(mod:SI (match_operand:SI 1 "register_operand" "0")
		(match_operand:SI 2 "register_operand" "r")))]
  ""
  "rem %0,%2"
  [(set_attr "type" "div4")
   (set_attr "length" "4")])

(define_insn "umodsi3"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(umod:SI (match_operand:SI 1 "register_operand" "0")
		 (match_operand:SI 2 "register_operand" "r")))]
  ""
  "remu %0,%2"
  [(set_attr "type" "div4")
   (set_attr "length" "4")])

;; Boolean instructions.
;;
;; We don't define the DImode versions as expand_binop does a good enough job.
;; And if it doesn't it should be fixed.

(define_insn "andsi3"
  [(set (match_operand:SI 0 "register_operand" "=r,r")
	(and:SI (match_operand:SI 1 "register_operand" "%0,r")
		(match_operand:SI 2 "reg_or_uint16_operand" "r,K")))]
  ""
  "*
{
  /* If we are worried about space, see if we can break this up into two
     short instructions, which might eliminate a NOP being inserted.  */
  if (optimize_size
      && m32r_not_same_reg (operands[0], operands[1])
      && GET_CODE (operands[2]) == CONST_INT
      && INT8_P (INTVAL (operands[2])))
    return \"#\";

  else if (GET_CODE (operands[2]) == CONST_INT)
    return \"and3 %0,%1,%#%X2\";

  return \"and %0,%2\";
}"
  [(set_attr "type" "int2,int4")
   (set_attr "length" "2,4")])

(define_split
  [(set (match_operand:SI 0 "register_operand" "")
	(and:SI (match_operand:SI 1 "register_operand" "")
		(match_operand:SI 2 "int8_operand" "")))]
  "optimize_size && m32r_not_same_reg (operands[0], operands[1])"
  [(set (match_dup 0) (match_dup 2))
   (set (match_dup 0) (and:SI (match_dup 0) (match_dup 1)))]
  "")

(define_insn "iorsi3"
  [(set (match_operand:SI 0 "register_operand" "=r,r")
	(ior:SI (match_operand:SI 1 "register_operand" "%0,r")
		(match_operand:SI 2 "reg_or_uint16_operand" "r,K")))]
  ""
  "*
{
  /* If we are worried about space, see if we can break this up into two
     short instructions, which might eliminate a NOP being inserted.  */
  if (optimize_size
      && m32r_not_same_reg (operands[0], operands[1])
      && GET_CODE (operands[2]) == CONST_INT
      && INT8_P (INTVAL (operands[2])))
    return \"#\";

  else if (GET_CODE (operands[2]) == CONST_INT)
    return \"or3 %0,%1,%#%X2\";

  return \"or %0,%2\";
}"
  [(set_attr "type" "int2,int4")
   (set_attr "length" "2,4")])

(define_split
  [(set (match_operand:SI 0 "register_operand" "")
	(ior:SI (match_operand:SI 1 "register_operand" "")
		(match_operand:SI 2 "int8_operand" "")))]
  "optimize_size && m32r_not_same_reg (operands[0], operands[1])"
  [(set (match_dup 0) (match_dup 2))
   (set (match_dup 0) (ior:SI (match_dup 0) (match_dup 1)))]
  "")

(define_insn "xorsi3"
  [(set (match_operand:SI 0 "register_operand" "=r,r")
	(xor:SI (match_operand:SI 1 "register_operand" "%0,r")
		(match_operand:SI 2 "reg_or_uint16_operand" "r,K")))]
  ""
  "*
{
  /* If we are worried about space, see if we can break this up into two
     short instructions, which might eliminate a NOP being inserted.  */
  if (optimize_size
      && m32r_not_same_reg (operands[0], operands[1])
      && GET_CODE (operands[2]) == CONST_INT
      && INT8_P (INTVAL (operands[2])))
    return \"#\";

  else if (GET_CODE (operands[2]) == CONST_INT)
    return \"xor3 %0,%1,%#%X2\";

  return \"xor %0,%2\";
}"
  [(set_attr "type" "int2,int4")
   (set_attr "length" "2,4")])

(define_split
  [(set (match_operand:SI 0 "register_operand" "")
	(xor:SI (match_operand:SI 1 "register_operand" "")
		(match_operand:SI 2 "int8_operand" "")))]
  "optimize_size && m32r_not_same_reg (operands[0], operands[1])"
  [(set (match_dup 0) (match_dup 2))
   (set (match_dup 0) (xor:SI (match_dup 0) (match_dup 1)))]
  "")

(define_insn "negsi2"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(neg:SI (match_operand:SI 1 "register_operand" "r")))]
  ""
  "neg %0,%1"
  [(set_attr "type" "int2")
   (set_attr "length" "2")])

(define_insn "one_cmplsi2"
  [(set (match_operand:SI 0 "register_operand" "=r")
	(not:SI (match_operand:SI 1 "register_operand" "r")))]
  ""
  "not %0,%1"
  [(set_attr "type" "int2")
   (set_attr "length" "2")])

;; Shift instructions.

(define_insn "ashlsi3"
  [(set (match_operand:SI 0 "register_operand" "=r,r,r")
	(ashift:SI (match_operand:SI 1 "register_operand" "0,0,r")
		   (match_operand:SI 2 "reg_or_uint16_operand" "r,O,K")))]
  ""
  "@
   sll %0,%2
   slli %0,%#%2
   sll3 %0,%1,%#%2"
  [(set_attr "type" "shift2,shift2,shift4")
   (set_attr "length" "2,2,4")])

(define_insn "ashrsi3"
  [(set (match_operand:SI 0 "register_operand" "=r,r,r")
	(ashiftrt:SI (match_operand:SI 1 "register_operand" "0,0,r")
		     (match_operand:SI 2 "reg_or_uint16_operand" "r,O,K")))]
  ""
  "@
   sra %0,%2
   srai %0,%#%2
   sra3 %0,%1,%#%2"
  [(set_attr "type" "shift2,shift2,shift4")
   (set_attr "length" "2,2,4")])

(define_insn "lshrsi3"
  [(set (match_operand:SI 0 "register_operand" "=r,r,r")
	(lshiftrt:SI (match_operand:SI 1 "register_operand" "0,0,r")
		     (match_operand:SI 2 "reg_or_uint16_operand" "r,O,K")))]
  ""
  "@
   srl %0,%2
   srli %0,%#%2
   srl3 %0,%1,%#%2"
  [(set_attr "type" "shift2,shift2,shift4")
   (set_attr "length" "2,2,4")])

;; Compare instructions.
;; This controls RTL generation and register allocation.

;; We generate RTL for comparisons and branches by having the cmpxx 
;; patterns store away the operands.  Then the bcc patterns
;; emit RTL for both the compare and the branch.
;;
;; On the m32r it is more efficient to use the bxxz instructions and
;; thus merge the compare and branch into one instruction, so they are
;; preferred.

(define_expand "cmpsi"
  [(set (reg:SI 17)
	(compare:CC (match_operand:SI 0 "register_operand" "")
		    (match_operand:SI 1 "reg_or_cmp_int16_operand" "")))]
  ""
  "
{
  m32r_compare_op0 = operands[0];
  m32r_compare_op1 = operands[1];
  DONE;
}")

(define_insn "cmp_eqsi_zero_insn"
  [(set (reg:SI 17)
        (eq:SI (match_operand:SI 0 "register_operand" "r,r")
               (match_operand:SI 1 "reg_or_zero_operand" "r,P")))]
  "TARGET_M32RX"
  "@
   cmpeq %0, %1
   cmpz  %0"
  [(set_attr "type" "int4")
   (set_attr "length" "4")])

;; The cmp_xxx_insn patterns set the condition bit to the result of the
;; comparison.  There isn't a "compare equal" instruction so cmp_eqsi_insn
;; is quite inefficient.  However, it is rarely used.

(define_insn "cmp_eqsi_insn"
  [(set (reg:SI 17)
        (eq:SI (match_operand:SI 0 "register_operand" "r,r")
               (match_operand:SI 1 "reg_or_cmp_int16_operand" "r,P")))
   (clobber (match_scratch:SI 2 "=&r,&r"))]
  ""
  "*
{
  if (which_alternative == 0)
    {
         return \"mv %2,%0\;sub %2,%1\;cmpui %2,#1\";
    }
  else
    {
        if (INTVAL (operands [1]) == 0)
          return \"cmpui %0, #1\";
        else if (REGNO (operands [2]) == REGNO (operands [0]))
          return \"addi %0,%#%N1\;cmpui %2,#1\";
        else
          return \"add3 %2,%0,%#%N1\;cmpui %2,#1\";
    }
}"
  [(set_attr "type" "multi,multi")
   (set_attr "length" "8,8")])

(define_insn "cmp_ltsi_insn"
  [(set (reg:SI 17)
        (lt:SI (match_operand:SI 0 "register_operand" "r,r")
               (match_operand:SI 1 "reg_or_int16_operand" "r,J")))]
  ""
  "@
   cmp %0,%1
   cmpi %0,%#%1"
  [(set_attr "type" "int2,int4")
   (set_attr "length" "2,4")])

(define_insn "cmp_ltusi_insn"
  [(set (reg:SI 17)
        (ltu:SI (match_operand:SI 0 "register_operand" "r,r")
                (match_operand:SI 1 "reg_or_int16_operand" "r,J")))]
  ""
  "@
   cmpu %0,%1
   cmpui %0,%#%1"
  [(set_attr "type" "int2,int4")
   (set_attr "length" "2,4")])


;; reg == small constant comparisons are best handled by putting the result
;; of the comparison in a tmp reg and then using beqz/bnez.
;; ??? The result register doesn't contain 0/STORE_FLAG_VALUE,
;; it contains 0/nonzero.

(define_insn "cmp_ne_small_const_insn"
  [(set (match_operand:SI 0 "register_operand" "=r,r")
	(ne:SI (match_operand:SI 1 "register_operand" "0,r")
	       (match_operand:SI 2 "cmp_int16_operand" "N,P")))]
  ""
  "@
   addi %0,%#%N2
   add3 %0,%1,%#%N2"
  [(set_attr "type" "int2,int4")
   (set_attr "length" "2,4")])

;; These control RTL generation for conditional jump insns.

(define_expand "beq"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (EQ, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "bne"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (NE, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "bgt"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (GT, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "ble"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (LE, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "bge"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (GE, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "blt"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (LT, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "bgtu"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (GTU, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "bleu"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (LEU, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "bgeu"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (GEU, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

(define_expand "bltu"
  [(set (pc)
	(if_then_else (match_dup 1)
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "
{
  operands[1] = gen_compare (LTU, m32r_compare_op0, m32r_compare_op1, FALSE);
}")

;; Now match both normal and inverted jump.

(define_insn "*branch_insn"
  [(set (pc)
	(if_then_else (match_operator 1 "eqne_comparison_operator"
				      [(reg 17) (const_int 0)])
		      (label_ref (match_operand 0 "" ""))
		      (pc)))]
  ""
  "*
{
  static char instruction[40];
  sprintf (instruction, \"%s%s %%l0\",
	   (GET_CODE (operands[1]) == NE) ? \"bc\" : \"bnc\",
	   (get_attr_length (insn) == 2) ? \".s\" : \"\");
  return instruction;
}"
  [(set_attr "type" "branch")
   ; We use 400/800 instead of 512,1024 to account for inaccurate insn
   ; lengths and insn alignments that are complex to track.
   ; It's not important that we be hyper-precise here.  It may be more
   ; important blah blah blah when the chip supports parallel execution
   ; blah blah blah but until then blah blah blah this is simple and