diff options
Diffstat (limited to 'libgcc/config')
| -rw-r--r-- | libgcc/config/avr/lib1funcs.S | 137 | ||||
| -rw-r--r-- | libgcc/config/avr/t-avr | 1 |
2 files changed, 137 insertions, 1 deletions
diff --git a/libgcc/config/avr/lib1funcs.S b/libgcc/config/avr/lib1funcs.S index 8c369c96a77..cd88a57bce7 100644 --- a/libgcc/config/avr/lib1funcs.S +++ b/libgcc/config/avr/lib1funcs.S @@ -599,7 +599,142 @@ ENDF __divmodhi4 #undef r_arg2L #undef r_cnt - + +/******************************************************* + Division 24 / 24 => (result + remainder) +*******************************************************/ + +;; A[0..2]: In: Dividend; Out: Quotient +#define A0 22 +#define A1 A0+1 +#define A2 A0+2 + +;; B[0..2]: In: Divisor; Out: Remainder +#define B0 18 +#define B1 B0+1 +#define B2 B0+2 + +;; C[0..2]: Expand remainder +#define C0 __zero_reg__ +#define C1 26 +#define C2 25 + +;; Loop counter +#define r_cnt 21 + +#if defined (L_udivmodpsi4) +;; R24:R22 = R24:R22 udiv R20:R18 +;; R20:R18 = R24:R22 umod R20:R18 +;; Clobbers: R21, R25, R26 + +DEFUN __udivmodpsi4 + ; init loop counter + ldi r_cnt, 24+1 + ; Clear remainder and carry. C0 is already 0 + clr C1 + sub C2, C2 + ; jump to entry point + rjmp __udivmodpsi4_start +__udivmodpsi4_loop: + ; shift dividend into remainder + rol C0 + rol C1 + rol C2 + ; compare remainder & divisor + cp C0, B0 + cpc C1, B1 + cpc C2, B2 + brcs __udivmodpsi4_start ; remainder <= divisor + sub C0, B0 ; restore remainder + sbc C1, B1 + sbc C2, B2 +__udivmodpsi4_start: + ; shift dividend (with CARRY) + rol A0 + rol A1 + rol A2 + ; decrement loop counter + dec r_cnt + brne __udivmodpsi4_loop + com A0 + com A1 + com A2 + ; div/mod results to return registers + ; remainder + mov B0, C0 + mov B1, C1 + mov B2, C2 + clr __zero_reg__ ; C0 + ret +ENDF __udivmodpsi4 +#endif /* defined (L_udivmodpsi4) */ + +#if defined (L_divmodpsi4) +;; R24:R22 = R24:R22 div R20:R18 +;; R20:R18 = R24:R22 mod R20:R18 +;; Clobbers: T, __tmp_reg__, R21, R25, R26 + +DEFUN __divmodpsi4 + ; R0.7 will contain the sign of the result: + ; R0.7 = A.sign ^ B.sign + mov __tmp_reg__, B2 + ; T-flag = sign of dividend + bst A2, 7 + brtc 0f + com __tmp_reg__ + ; Adjust dividend's sign + rcall __divmodpsi4_negA +0: + ; Adjust divisor's sign + sbrc B2, 7 + rcall __divmodpsi4_negB + + ; Do the unsigned div/mod + XCALL __udivmodpsi4 + + ; Adjust quotient's sign + sbrc __tmp_reg__, 7 + rcall __divmodpsi4_negA + + ; Adjust remainder's sign + brtc __divmodpsi4_end + +__divmodpsi4_negB: + ; Correct divisor/remainder sign + com B2 + com B1 + neg B0 + sbci B1, -1 + sbci B2, -1 + ret + + ; Correct dividend/quotient sign +__divmodpsi4_negA: + com A2 + com A1 + neg A0 + sbci A1, -1 + sbci A2, -1 +__divmodpsi4_end: + ret + +ENDF __divmodpsi4 +#endif /* defined (L_divmodpsi4) */ + +#undef A0 +#undef A1 +#undef A2 + +#undef B0 +#undef B1 +#undef B2 + +#undef C0 +#undef C1 +#undef C2 + +#undef r_cnt + /******************************************************* Division 32 / 32 => (result + remainder) *******************************************************/ diff --git a/libgcc/config/avr/t-avr b/libgcc/config/avr/t-avr index a669f61629a..63f7460e2b3 100644 --- a/libgcc/config/avr/t-avr +++ b/libgcc/config/avr/t-avr @@ -12,6 +12,7 @@ LIB1ASMFUNCS = \ _divmodqi4 \ _udivmodhi4 \ _divmodhi4 \ + _divmodpsi4 _udivmodpsi4 \ _udivmodsi4 \ _divmodsi4 \ _prologue \ |