more comments

This commit is contained in:
Jeff Wang 2019-09-24 00:11:51 -04:00
parent 4f020da222
commit 6eb48de844

View File

@ -657,6 +657,8 @@ void add_decn(void){
}
}
//AccDecn *= BDecn
// (the BDecn register is preserved)
void mult_decn(void){
int8_t i, j;
uint8_t carry = 0;
@ -801,30 +803,35 @@ void div_decn(void){
decn_to_str_complete(&curr_recip);
printf("%2d: %s\n", i, Buf);
#endif
//Accum *= x_copy
copy_decn(&BDecn, &X_COPY);
mult_decn();
#ifdef DEBUG_DIV
decn_to_str_complete(&AccDecn);
printf(" %20s: %s\n", "recip*x", Buf);
#endif
//Accum *= -1
negate_decn(&AccDecn);
//Accum += 1
copy_decn(&BDecn, &DECN_1);
add_decn();
#ifdef DEBUG_DIV
decn_to_str_complete(&AccDecn);
printf(" %20s: %s\n", "(1-recip*x)", Buf);
#endif
//Accum *= curr_recip
copy_decn(&BDecn, &CURR_RECIP);
mult_decn();
#ifdef DEBUG_DIV
decn_to_str_complete(&AccDecn);
printf(" %20s: %s\n", "recip * (1-recip*x)", Buf);
#endif
//Accum += curr_recip
add_decn();
//new_est(acc) = recip + (1 - recip*x)*recip, where tmp is current recip estimate
//new_est(Accum) = recip + (1 - recip*x)*recip, where recip is current recip estimate
copy_decn(&CURR_RECIP, &AccDecn);
}
//acc now holds 1/x, multiply by original acc to complete division
//Accum now holds 1/x, multiply by original acc to complete division
copy_decn(&BDecn, &ACC_COPY);
mult_decn();