From 71354d0f866722b8baeeb05f1fedac5809558ce2 Mon Sep 17 00:00:00 2001 From: Simon Brooke Date: Fri, 15 Feb 2019 14:19:41 +0000 Subject: [PATCH] Woohoo! Actual goddamned progress! Multiply might be working! Print definitely isn't! --- src/arith/integer.c | 111 +++++++++++++++++++++++++------------------- src/io/print.c | 2 +- 2 files changed, 64 insertions(+), 49 deletions(-) diff --git a/src/arith/integer.c b/src/arith/integer.c index 48992ca..db6f71c 100644 --- a/src/arith/integer.c +++ b/src/arith/integer.c @@ -216,6 +216,27 @@ struct cons_pointer base_partial( int depth ) { return result; } +/** + * destructively modify this `partial` by appending this `digit`. + */ +struct cons_pointer append_digit( struct cons_pointer partial, struct cons_pointer digit) { + struct cons_pointer c = partial; + struct cons_pointer result = partial; + + if (nilp( partial)) { + result = digit; + } else { + while ( !nilp( pointer2cell(c).payload.integer.more)) { + c = pointer2cell(c).payload.integer.more; + } + + (&pointer2cell(c))->payload.integer.more = digit; + } + return result; +} + + + /** * Return a pointer to an integer representing the product of the integers * pointed to by `a` and `b`. If either isn't an integer, will return nil. @@ -225,11 +246,11 @@ struct cons_pointer base_partial( int depth ) { * @param b an integer. */ struct cons_pointer multiply_integers( struct cons_pointer a, - struct cons_pointer b ) { - struct cons_pointer result = NIL; + struct cons_pointer b ) { + struct cons_pointer result = make_integer( 0, NIL); bool neg = is_negative( a ) != is_negative( b ); bool is_first_b = true; - int oom = -1; + int i = 0; debug_print( L"multiply_integers: a = ", DEBUG_ARITH ); debug_print_object( a, DEBUG_ARITH ); @@ -238,60 +259,54 @@ struct cons_pointer multiply_integers( struct cons_pointer a, debug_println( DEBUG_ARITH ); if ( integerp( a ) && integerp( b ) ) { - while ( !nilp( b ) ) { - bool is_first_d = true; - struct cons_pointer d = a; - struct cons_pointer partial = base_partial( ++oom ); + /* for each digit in a, starting with the least significant (ai) */ + + for ( struct cons_pointer ai = a; !nilp( ai ); + ai = pointer2cell(ai).payload.integer.more) { + /* set carry to 0 */ __int128_t carry = 0; - while ( !nilp( d ) || carry != 0 ) { - partial = make_integer( 0, partial ); - struct cons_pointer new = NIL; - __int128_t dv = cell_value( d, '+', is_first_d ); - __int128_t bv = cell_value( b, '+', is_first_b ); + /* set least significant digits for result ri for this iteration + * to i zeros */ + struct cons_pointer ri = base_partial( i++ ); - __int128_t rv = ( dv * bv ) + carry; + /* for each digit in b, starting with the least significant (bj) */ + for ( struct cons_pointer bj = b; !nilp( bj ); + bj = pointer2cell(bj).payload.integer.more) { - debug_print( L"multiply_integers: d = ", DEBUG_ARITH ); - debug_print_object( d, DEBUG_ARITH ); - debug_print( L"; dv = ", DEBUG_ARITH ); - debug_print_128bit( dv, DEBUG_ARITH ); - debug_print( L"; bv = ", DEBUG_ARITH ); - debug_print_128bit( bv, DEBUG_ARITH ); - debug_print( L"; carry = ", DEBUG_ARITH ); - debug_print_128bit( carry, DEBUG_ARITH ); - debug_print( L"; rv = ", DEBUG_ARITH ); - debug_print_128bit( rv, DEBUG_ARITH ); - debug_print( L"; acc = ", DEBUG_ARITH ); - debug_print_object( result, DEBUG_ARITH ); - debug_print( L"; partial = ", DEBUG_ARITH ); - debug_print_object( partial, DEBUG_ARITH ); - debug_print( L"\n", DEBUG_ARITH ); + debug_printf( DEBUG_ARITH, + L"multiply_integers: a[i] = %Ld, b[j] = %Ld, i = %d\n", + pointer2cell(ai).payload.integer.value, + pointer2cell(bj).payload.integer.value, i); - new = make_integer_128( rv, base_partial( oom ) ); + /* multiply ai with bj and add the carry, resulting in a + * value xj which may exceed one digit */ + __int128_t xj = pointer2cell(ai).payload.integer.value * + pointer2cell(bj).payload.integer.value; + xj += carry; - if ( zerop( partial ) ) { - partial = new; - } else { - partial = add_integers( partial, new ); - } + /* if xj exceeds one digit, break it into the digit dj and + * the carry */ + carry = xj >> 60; + struct cons_pointer dj = make_integer( xj & MAX_INTEGER, NIL); - d = integerp( d ) ? pointer2cell( d ).payload.integer. - more : NIL; - is_first_d = false; + /* destructively modify ri by appending dj */ + ri = append_digit( ri, dj); + } /* end for bj */ + + /* if carry is not equal to zero, append it as a final digit + * to ri */ + if (carry != 0) { + ri = append_digit( ri, make_integer( carry, NIL)); } - if ( nilp( result ) || zerop( result ) ) { - result = partial; - } else { - struct cons_pointer old = result; - result = add_integers( partial, result ); - //if (!eq(result, old)) dec_ref(old); - //if (!eq(result, partial)) dec_ref(partial); - } - b = pointer2cell( b ).payload.integer.more; - is_first_b = false; - } + /* add ri to result */ + result = add_integers( result, ri); + + debug_print( L"multiply_integers: result is ", DEBUG_ARITH ); + debug_print_object( result, DEBUG_ARITH ); + debug_println( DEBUG_ARITH ); + } /* end for ai */ } debug_print( L"multiply_integers returning: ", DEBUG_ARITH ); diff --git a/src/io/print.c b/src/io/print.c index c886981..f0db8cd 100644 --- a/src/io/print.c +++ b/src/io/print.c @@ -163,7 +163,7 @@ struct cons_pointer print( URL_FILE * output, struct cons_pointer pointer ) { print_list( output, pointer ); break; case EXCEPTIONTV: - url_fwuts( L"\nException: ", output ); + url_fputws( L"\nException: ", output ); dump_stack_trace( output, pointer ); break; case FUNCTIONTV: