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/************************  guess_number.as  **********************************

* Author:        Agner Fog

* date created:  2018-02-23

* last modified: 2021-08-04

* Version:       1.11

* Project:       ForwardCom example, assembly code

* Description:   Guessing game. Guess a number 1 - 100

*

* Copyright 2018-2021 GNU General Public License http://www.gnu.org/licenses

*****************************************************************************/

%buffersize = 0x20                               // size of input text buffer

%maxnum = 100                                    // maximum number

const section read ip                            // read-only data section

intro:    int8 "\nGuessing game. Guess a number 1 - %i\n",0  // format string

guess:    int8 "Your guess:",0                               // text

smaller:  int8 "\nSmaller",0                                 // text

bigger:   int8 "\nBigger",0                                  // text

conclude: int8 "\nYou guessed the number %i in %i tries",0   // format string

another:  int8 "\nAnother? (y/n) ",0                         // text

goodbye:  int8 "\nGoodbye", 0                                // text

const end

bss section datap uninitialized                  // uninitialized read/write data section

int64 parlist[4]                                 // parameter list for printf

int8 buf[buffersize]                             // input buffer

bss end

code section execute                             // code section

extern _puts: function                           // library function: write string to stdout

extern _gets_s: function                         // library function: read string from stdin

extern _printf: function                         // library function: formatted output to stdout

extern _atoi: function                           // library function: convert string to integer

extern _divide_int: function                     // library function: divide intergers (if core has no division instruction)

_main function public                            // program begins here

do {                                             // loop to repeat game

   int64 r0 = address([intro])                   // format string to printf

   int64 r1 = address([parlist])                 // parameter list

   int32 [r1] = maxnum                           // put maxnum in parameter list

   call _printf                                  // printf("\nguess a number 1 - %i\n", maxnum);

   int32 r0 = read_perf(perf1,1)                 // read CPU clock counter to use as a random number

   uint32 r0 = abs(r0,1)                         // avoid negative numbers

   //call _time                                  // or use time as random number

   // get number modulo maxnum (0 - 99)

   //uint32 r1 = r0 % maxnum                     // use this if core has division instruction

   int32 r1 = maxnum

   call _divide_int                              // this function returns a/b in r0 and a%b in r1

   int32 r16 = r1 + 1                            // number to guess (1 - 100)

   for (int64 r17 = 1; ; r17++) {                // loop to guess number. no exit condition here

      int64 r0 = address([guess])

      call _puts                                 // write "your guess"

      int64 r0 = address([buf])

      int64 r1 = buffersize

      call _gets_s                               // read input into buffer

      int64 r0 = address([buf])

      call _atoi                                 // convert string to integer

      if (int32 r0 == r16) {break}               // guess is correct. stop 'for' loop

      if (int32 r16 < r0) {                      // select text: "smaller" or "bigger"

         int64 r0 = address([smaller])

      }

      else {

         int64 r0 = address([bigger])

      }

      call _puts                                 // write "smaller" or "bigger"

   }

   // guessing loop is finished

   int64 r0 = address([conclude])                // format string for printf

   int64 r1 = address([parlist])                 // parameter list

   int32 [r1] = r16                              // put guessed number in parameter list

   int32 [r1+8] = r17                            // put number of tries in parameter list

   call  _printf                                 // printf("\nyou guessed the number %i in %i tries", r16, r17)

   int64 r0 = address([another])

   call  _puts                                   // write "\nanother? (y/n) "

   int64 r0 = address([buf])

   int64 r1 = buffersize

   call  _gets_s                                 // read answer into buffer

   int8  r0 = [buf]                              // get first character of answer, ignore the rest

   int8+ r0 |= 0x20                              // convert to lower case

}

while (int8 r0 == 'y')                           // repeat 'do' loop if answer is "y"

int64 r0 = address([goodbye])

call _puts                                       // write "goodbye"

int r0 = 0                                       // program return value

return                                           // return from main

_main end

code end