189 lines
3.9 KiB
Text
189 lines
3.9 KiB
Text
.constant
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OBJREF 0x40
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.end-constant
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.main
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.var
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a
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b
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min
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.end-var
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LDC_W OBJREF
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INVOKEVIRTUAL getnum
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ISTORE a
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LDC_W OBJREF
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INVOKEVIRTUAL getnum
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ISTORE b
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ILOAD a
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ILOAD b
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LDC_W OBJREF
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INVOKEVIRTUAL min
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HALT
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.end-main
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.method min(x,y)
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.var
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.end-var
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ILOAD x
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ILOAD y
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ISUB
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IFLT returny
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ILOAD x
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IRETURN
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returny:
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ILOAD y
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IRETURN
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.end-method
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.method getnum()
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.var
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a
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.end-var
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BIPUSH 0x0 // initialize a
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ISTORE a
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geta: IN // read key press
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DUP // duplicate key for comparison
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BIPUSH 0xa // if key = cr,
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IF_ICMPEQ return // return
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DUP
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BIPUSH 0x30 // if key < "0"
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ISUB //
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IFLT geta4 // goto geta4 (key is not a hex digit)
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DUP
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BIPUSH 0x3a // else if key < ":"
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ISUB //
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IFLT geta2 // goto geta2 (key is numeric character - "0"-"9")
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DUP
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BIPUSH 0x41 // else if key < "A"
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ISUB //
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IFLT geta4 // goto geta4 (key is not a hex digit)
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DUP
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BIPUSH 0x46 // else if key > "F"
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SWAP //
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ISUB //
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IFLT geta4 // goto geta4 (key is not a hex digit)
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DUP // else (key is letter - "A"-"F")
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OUT // print key
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BIPUSH 0x37 // convert key from character to number
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ISUB //
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GOTO geta3 // goto geta3
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geta2: DUP
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OUT // print key (numeric character)
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BIPUSH 0x30 // convert key from character to number
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ISUB
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geta3: ILOAD a // shift a left 8 bits
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DUP
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IADD
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DUP
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IADD
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DUP
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IADD
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DUP
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IADD
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IADD // add key to a
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ISTORE a
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GOTO geta // get next key
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geta4: POP // pop invalid character
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GOTO geta // get next key
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return: OUT // print cr
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ILOAD a // load a as return value
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IRETURN // return
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.end-method
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.method print( total ) // print converts a number into a string of
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// characters and prints them. All of the characters
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// are pushed onto the stack, least significant
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// digit first, then popped off and printed.
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.var
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place
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index
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.end-var
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print: BIPUSH 0x9 // there are 8 nibbles in each integer--setting
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// this as nine pushes 10 characters onto the
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// stack, thus a total of ten printed digits,
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// but setting this less does not remove the
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// two leading zeros, just removes significant
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// digits
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ISTORE index
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BIPUSH 0x1 // comparison bit
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ISTORE place
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print1: BIPUSH 0x0
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ILOAD index // index = index - 1
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BIPUSH 0x1
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ISUB
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DUP
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IFEQ pall // if index = 0 goto pall
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ISTORE index
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ILOAD total // else
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ILOAD place //
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IAND // if 1st bit of current nibble is zero (total & place)
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IFEQ print2 // goto print2
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BIPUSH 0x1 // else set first bit of character
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IADD
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print2: ILOAD place // place = place << 1
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DUP
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IADD
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ISTORE place
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ILOAD total
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ILOAD place
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IAND // if 2nd bit of current nibble is zero (total & place)
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IFEQ print3 // goto print3
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BIPUSH 0x2 // else set second bit of character
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IADD
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print3: ILOAD place // place = place << 1
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DUP
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IADD
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ISTORE place
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ILOAD total
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ILOAD place
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IAND // if 3rd bit of current nibble is zero (total & place)
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IFEQ print4 // goto print4
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BIPUSH 0x4 // else set second bit of character
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IADD
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print4: ILOAD place // place = place << 1
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DUP
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IADD
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ISTORE place
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ILOAD total
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ILOAD place
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IAND // if 4th bit of current nibble is zero (total & place)
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IFEQ print5 // goto print5
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BIPUSH 0x8 // else set second bit of character
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IADD
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print5: ILOAD place // place = place << 1
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DUP
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IADD
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ISTORE place
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GOTO print1
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pall: POP // Pop off leading 0's
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POP
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BIPUSH 0x9
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ISTORE index
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pall1: ILOAD index // index = index - 1
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BIPUSH 0x1
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ISUB
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DUP
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IFEQ return // if index = 0 return
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ISTORE index
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DUP
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BIPUSH 0xa // else if character < 0xa goto pall1
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ISUB
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IFLT pall2
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BIPUSH 0x37 // else convert character to "A"-"F"
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IADD
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OUT // print character
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GOTO pall1 // goto pall (prepare & print next character)
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pall2: BIPUSH 0x30 // convert character to "0"-"9"
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IADD
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OUT // print character
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GOTO pall1 // goto pall1 (prepare & print next character)
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return: BIPUSH 0xa // print cr
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OUT
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IRETURN // no return value
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.end-method
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