cs350/kern/arch/mips/thread/threadstart.S

/*
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 *	The President and Fellows of Harvard College.
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 */

/*
 * Assembler-level thread startup trampoline.
 */

#include <kern/mips/regdefs.h>
  
   .text
   .set noreorder

   .globl mips_threadstart
   .type mips_threadstart,@function
   .ent mips_threadstart
mips_threadstart:

   /*
    * This code doesn't take normal arguments. It's reached when
    * switchframe_switch switches to a new thread. switchframe_switch
    * does "j ra"; ra gets preloaded in switchframe_init to come here.
    *
    * Our arguments are in callee-save registers, as follows:
    *
    *   s0   entrypoint
    *   s1   data1
    *   s2   data2
    *
    * We need to rearrange these so as to call the normal C function
    * thread_startup(void (*entrypoint)(), void *data1, unsigned long data2).
    */

   addiu sp, sp, -16    /* make our stack frame */
   
   move ra, $0          /* clear return addr so we're top of the call stack */

   move a0, s0          /* load arguments and call */
   move a1, s1
   j thread_startup
   move a2, s2          /* (in delay slot) */

   .end mips_threadstart