have to leave instrs.adb around, kernel uses it for kdb

[unix-history] / usr / src / sys / tahoe / align / Asbwc.c

/*      Asbwc.c 1.1     86/07/20        */


#include "../tahoealign/align.h" 
sbwc(infop)     process_info *infop;
/*
/*      Subtract with carry.
/*      Note : the play with 'tmp' just before the 'asm' line makes
/*              sure that when the sbwc opcode is executed, the current
/*              carry in psl is the same as the 'offending' process'.
/*              Don't change unless you know exactly what you're doing.
/*
/*****************************/
{
       register        long    Register_12;    /* Has to be first reg ! */
       register        long    Register_11;
       register        long    Register_10;
       register        long    tmp;

       Register_12 = operand(infop,0)->data;
       Register_11 = operand(infop,1)->data;
       if (carry)      /* If process' carry set */
               tmp = -1;
       else tmp = 0;
       tmp++;          /* 0 => carry set.  1 => carry clear */

       Register_10=psl;
       Set_psl(r10);   /* restore the user psl */
       asm("   sbwc    r12,r11");
       asm("   movpsl  r12");
       New_cc (Register_12);

       write_back(infop, Register_11, operand(infop,1) );
}