Xinu7/man/man3/eis.doc

EIS(3)              Xinu Programmer's Manual               EIS(3)



NAME
     EIS - extended instruction set for the LSI-11/2

SYNOPSIS
     jsr pc,times2
     jsr pc,over2
     jsr pc,shift2
     jsr pc,cshft2

DESCRIPTION
     Library _e_i_s._a contains assembly language routines to simu-
     late LSI-11 multiply, divide, arithmetic shift, and arith-
     metic shift combined instructions.  Normally, an assembly
     language listing should be filtered through the programs
     _s_u_b_M_U_L, _s_u_b_D_I_V, _s_u_b_A_S_H, and _s_u_b_A_S_H_C to replace any of the
     extended instructions with the proper calling sequence.  The
     resulting assembly language program must be loaded with this
     library, which contains the routines called.

     These routines do _n_o_t use the C calling conventions. The
     multiply routine is called by:
       mfps  -(sp)     / push psw
       mov   A,-(sp)   / push multiplier
       mov   R,-(sp)   / push multiplicand
       jsr   pc,times2 / call mul simulation routine
       mov   (sp)+,R   / save low word of product
       mov   (sp)+,R+1 / save high word of product
       mtps  (sp)+     / put in new psw
     where the instruction being mimicked is "mul A,R" and R is
     an even-numbered register (if R is odd, change the "mov
     (sp)+,R" to "tst (sp)+" and the "mov (sp)+,R+1" to "mov
     (sp)+,R").

     The division routine is called by:
       mfps  -(sp)     / push psw
       mov   A,-(sp)   / push divisor
       mov   R,-(sp)   / push high word of dividend
       mov   R+1,-(sp) / push low word of dividend
       jsr   pc,over2  / call div simulation routine
       mov   (sp)+,R+1 / save remainder
       mov   (sp)+,R   / save quotient
       tst   (sp)+     / reset stack pointer
       mtps  (sp)+     / put in new psw
     where the instruction being mimicked is "div A,R".

     The arithmetic shift routine is called by:
       mfps  -(sp)     / get psw
       mov   A,-(sp)   / push shift count onto the stack
       mov   r0,-(sp)  / push number to be shifted onto the stack
       jsr   pc,shift2 / call the simulation routine
       mov   (sp)+,r0  / save the result
       tst   (sp)+     / reset stack pointer



Version 6b               Printed 1/12/87                        1






EIS(3)              Xinu Programmer's Manual               EIS(3)



       mtps  (sp)+     / put in new psw
     where the instruction being mimicked is "ash A,R".  The
     arithmetic shift combined routine is called by:
       mfps  -(sp)     / get psw
       mov   A,-(sp)   / push shift count onto the stack
       mov   r0,-(sp)  / push high word onto the stack
       mov   r1,-(sp)  / push low word onto the stack
       jsr   pc,shift2 / call the simulation routine
       mov   (sp)+,r1  / save the low word
       mov   (sp)+,r0  / save the high word
       tst   (sp)+     / reset stack pointer
       mtps  (sp)+     / put in the new psw
     where the instruction being mimicked is "ashc A,R".

FILES
     {Xinu-directory}/lib/libeis.a
     {Xinu-directory}/bin/subMUL
     {Xinu-directory}/bin/subDIV
     {Xinu-directory}/bin/subASH
     {Xinu-directory}/bin/subASHC

SEE ALSO
     cc11(1), subEIS(1)

DIAGNOSTICS
     The condition codes are correctly set by the above calling
     sequence.




























Version 6b               Printed 1/12/87                        2