205 lines
3.2 KiB
ArmAsm
205 lines
3.2 KiB
ArmAsm
/* Start.s
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* Assembly language assist for user programs running on top of Nachos.
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*
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* Since we don't want to pull in the entire C library, we define
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* what we need for a user program here, namely Start and the system
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* calls.
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*/
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#define IN_ASM
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#include "syscall.h"
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.text
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.align 2
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/* -------------------------------------------------------------
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* __start
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* Initialize running a C program, by calling "main".
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*
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* NOTE: This has to be first, so that it gets loaded at location 0.
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* The Nachos kernel always starts a program by jumping to location 0.
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* -------------------------------------------------------------
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*/
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.globl __start
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.ent __start
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__start:
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jal main
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move $4,$0
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jal Exit /* if we return from main, exit(0) */
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.end __start
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/* -------------------------------------------------------------
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* System call stubs:
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* Assembly language assist to make system calls to the Nachos kernel.
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* There is one stub per system call, that places the code for the
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* system call into register r2, and leaves the arguments to the
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* system call alone (in other words, arg1 is in r4, arg2 is
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* in r5, arg3 is in r6, arg4 is in r7)
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*
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* The return value is in r2. This follows the standard C calling
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* convention on the MIPS.
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* -------------------------------------------------------------
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*/
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.globl Halt
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.ent Halt
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Halt:
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addiu $2,$0,SC_Halt
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syscall
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j $31
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.end Halt
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.globl MSG
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.ent MSG
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MSG:
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addiu $2,$0,SC_MSG
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syscall
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j $31
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.end MSG
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.globl Add
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.ent Add
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Add:
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addiu $2,$0,SC_Add
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syscall
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j $31
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.end Add
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.globl Exit
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.ent Exit
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Exit:
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addiu $2,$0,SC_Exit
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syscall
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j $31
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.end Exit
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.globl Exec
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.ent Exec
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Exec:
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addiu $2,$0,SC_Exec
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syscall
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j $31
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.end Exec
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.globl ExecV
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.ent ExecV
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ExecV:
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addiu $2,$0,SC_ExecV
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syscall
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j $31
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.end ExecV
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.globl Join
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.ent Join
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Join:
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addiu $2,$0,SC_Join
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syscall
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j $31
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.end Join
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.globl Create
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.ent Create
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Create:
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addiu $2,$0,SC_Create
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syscall
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j $31
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.end Create
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.globl Remove
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.ent Remove
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Remove:
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addiu $2,$0,SC_Remove
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syscall
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j $31
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.end Remove
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.globl Open
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.ent Open
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Open:
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addiu $2,$0,SC_Open
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syscall
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j $31
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.end Open
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.globl Read
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.ent Read
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Read:
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addiu $2,$0,SC_Read
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syscall
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j $31
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.end Read
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.globl Write
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.ent Write
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Write:
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addiu $2,$0,SC_Write
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syscall
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j $31
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.end Write
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.globl Close
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.ent Close
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Close:
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addiu $2,$0,SC_Close
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syscall
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j $31
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.end Close
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.globl Seek
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.ent Seek
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Seek:
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addiu $2,$0,SC_Seek
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syscall
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j $31
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.end Seek
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.globl ThreadFork
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.ent ThreadFork
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ThreadFork:
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addiu $2,$0,SC_ThreadFork
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syscall
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j $31
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.end ThreadFork
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.globl ThreadYield
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.ent ThreadYield
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ThreadYield:
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addiu $2,$0,SC_ThreadYield
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syscall
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j $31
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.end ThreadYield
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.globl ThreadExit
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.ent ThreadExit
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ThreadExit:
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addiu $2, $0, SC_ThreadExit
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syscall
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j $31
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.end ThreadExit
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.globl ThreadJoin
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.ent ThreadJoin
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ThreadJoin:
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addiu $2, $0, SC_ThreadJoin
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syscall
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j $31
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.end ThreadJoin
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.globl PrintInt
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.ent PrintInt
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PrintInt:
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addiu $2,$0,SC_PrintInt
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syscall
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j $31
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.end PrintInt
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/* dummy function to keep gcc happy */
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.globl __main
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.ent __main
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__main:
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j $31
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.end __main
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