pending/984: File I/O in H8300 Simulator

["D.Venkatasubramanian, Noida" <dvenkat at noida dot hcltech dot com>]

>Number:         984
>Category:       pending
>Synopsis:       File I/O in H8300 Simulator
>Confidential:   yes
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          change-request
>Submitter-Id:   unknown
>Arrival-Date:   Fri Jan 31 05:08:01 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     
>Release:        
>Organization:
>Environment:
>Description:
 Hi All,
 
 I was intending to add File I/O support to the H8300 simulator
 code. And the system calls that I was intending to modify were
 creat, open, read, write, seek and close.
 
 Since the support for read was present in the newlib, I started 
 out with adding reading from stdin support in the sim. I am 
 submitting a patch which does the same.
 
 I was thinking of adopting a similar strategy for handling the
 other system calls, (branch to some location like 0xc5, 0xc6 etc.)
 for different system calls and handle these through simulator. For
 these system calls, I need to do some modifications on newlib too.
 I may need to change the current implementation of read and write
 again to handle host files.
 
 Please let me know, if this is OK.
 
 Thanks and Regards,
 
 Venky
 
 
 *** include/opcode/h8300.h.original     Thu Oct 24 15:56:06 2002
 --- include/opcode/h8300.h.modified     Mon Oct 28 12:40:18 2002
 *************** struct h8_opcode
 *** 305,310 ****
 --- 305,317 ----
   #define O_STM 86
   #define O_STMAC 87
   #define O_LAST 88
 + /* Change made for System Call processing */
 + #define O_SYS_CREAT 100
 + #define O_SYS_OPEN 101
 + #define O_SYS_READ 102
 + #define O_SYS_WRITE 103
 + #define O_SYS_SEEK 104
 + /* End of Changes */
   #define SB 0
   #define SW 1
   #define SL 2
 *** sim/h8300/compile.c.original        Mon Oct 28 13:03:12 2002
 --- sim/h8300/compile.c.modified        Mon Oct 28 13:03:20 2002
 *************** decode (addr, data, dst)
 *** 448,464 ****
                   dst->opcode = q->how;
                   dst->cycles = q->time;
 
 !                 /* And a jsr to 0xc4 is turned into a magic trap.  */
 
                   if (dst->opcode == O (O_JSR, SB))
                     {
                       if (dst->src.literal == 0xc4)
                         {
 !                         dst->opcode = O (O_SYSCALL, SB);
                         }
                     }
 !
 !                 dst->next_pc = addr + len / 2;
                   return;
                 }
               else
 --- 448,469 ----
                   dst->opcode = q->how;
                   dst->cycles = q->time;
 
 !                 /* And a jsr to 0xc4 or 0xc8 is turned into a magic trap.
 */
 !                   /* System Call Processing */
 
                   if (dst->opcode == O (O_JSR, SB))
                     {
                       if (dst->src.literal == 0xc4)
                         {
 !                         dst->opcode = O (O_SYS_WRITE, SB);
 !                       }
 !                     else if (dst->src.literal == 0xc8)
 !                       {
 !                         dst->opcode = O (O_SYS_READ, SB);
                         }
                     }
 !
 !                   dst->next_pc = addr + len / 2;
                   return;
                 }
               else
 *************** sim_resume (sd, step, siggnal)
 *** 1392,1405 ****
             goto condtrue;
           goto next;
 
 !         case O (O_SYSCALL, SB):
             {
             char c = cpu.regs[2];
             sim_callback->write_stdout (sim_callback, &c, 1);
           }
             goto next;
 
 !         ONOT (O_NOT, rd = ~rd; v = 0;);
           OSHIFTS (O_SHLL,
                    c = rd & hm; v = 0; rd <<= 1,
                    c = rd & (hm >> 1); v = 0; rd <<= 2);
 --- 1397,1418 ----
             goto condtrue;
           goto next;
 
 ! /* System Call Processing */
 !       case O (O_SYS_WRITE, SB):
             {
             char c = cpu.regs[2];
             sim_callback->write_stdout (sim_callback, &c, 1);
           }
             goto next;
 +         case O (O_SYS_READ, SB):
 +           {
 +           char d ;
 +           sim_callback->read_stdin (sim_callback, &d, 1);
 +             SET_MEMORY_B (cpu.regs[2], d);
 +         }
 +         goto next;
 
 !           ONOT (O_NOT, rd = ~rd; v = 0;);
           OSHIFTS (O_SHLL,
                    c = rd & hm; v = 0; rd <<= 1,
                    c = rd & (hm >> 1); v = 0; rd <<= 2);
 
 
 
 
 Change Log entries
 
 Mon Oct 28 14:12:42 IST 2002 D.Venkatasubramanian
 <dvenkat@noida.hcltech.com>
 
         * compile.c (decode): Added code to recognize a read system
         call and modified to recognize write system call.
 
         * compile.c (sim_resume): Added code for handling read system
         call and modified code for write.
 
 
 Mon Oct 28 12:41:37 IST 2002 D.Venkatasubramanian
 <dvenkat@noida.hcltech.com>
 
         * h8300.h : Added some # defines for system call processing.
         These system calls are being introduced as pseudo opcodes
         for system call handling in the simulator. This is similar
         to the O_SYSCALL entry already present.
 
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