[avr-gcc-list] [patch] AVR __mulhi3 fix

[Marek Michalkiewicz]

I've just applied this, for now to the 3.1 tree - fixes an old but
serious bug (513 * 1 = 1) so I'm afraid it should go into 3.0 as well...


2001-03-28  Marek Michalkiewicz  <address@hidden>

        * config/avr/libgcc.S (__mulhi3): Correct tests to exit the loop
        when multiplier or multiplicand is zero.


Index: config/avr/libgcc.S
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/avr/libgcc.S,v
retrieving revision 1.11
diff -c -3 -p -r1.11 libgcc.S
*** libgcc.S    2001/01/21 07:08:46     1.11
--- libgcc.S    2001/03/28 17:00:46
*************** __mulhi3_skip1: 
*** 137,147 ****
        add     r_arg2L,r_arg2L ; shift multiplicand
        adc     r_arg2H,r_arg2H
  
!       cpc     r_arg2L,__zero_reg__
        breq    __mulhi3_exit   ; while multiplicand != 0
  
        lsr     r_arg1H         ; gets LSB of multiplier
        ror     r_arg1L
        cpc     r_arg1H,__zero_reg__
        brne    __mulhi3_loop   ; exit if multiplier = 0
  __mulhi3_exit:
--- 137,149 ----
        add     r_arg2L,r_arg2L ; shift multiplicand
        adc     r_arg2H,r_arg2H
  
!       cp      r_arg2L,__zero_reg__
!       cpc     r_arg2H,__zero_reg__
        breq    __mulhi3_exit   ; while multiplicand != 0
  
        lsr     r_arg1H         ; gets LSB of multiplier
        ror     r_arg1L
+       cp      r_arg1L,__zero_reg__
        cpc     r_arg1H,__zero_reg__
        brne    __mulhi3_loop   ; exit if multiplier = 0
  __mulhi3_exit: