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added some code to handle right-shift of a negative number

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hyunghwan.chung 2015-12-23 15:25:29 +00:00
parent e7d00d89bf
commit 2022ac965b
2 changed files with 105 additions and 15 deletions
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10
stix/kernel/test-005.st
View File

@ -356,6 +356,7 @@ PROCESS TESTING
((2r1111111 bitInvert) printStringRadix: 16) dump. ((2r1111111 bitInvert) printStringRadix: 16) dump.
((2r11001110000000000000000000000000000000000000000000000000000000000000000000000 bitInvert) printStringRadix: 16) dump. ((2r11001110000000000000000000000000000000000000000000000000000000000000000000000 bitInvert) printStringRadix: 16) dump.
((2r1111 bitShift: 100) printStringRadix: 2) dump. ((2r1111 bitShift: 100) printStringRadix: 2) dump.
((123123124 bitShift: 100000) printStringRadix: 16) dump. ((123123124 bitShift: 100000) printStringRadix: 16) dump.
(2r110101010101010101010101010101111111111111111111111111111111111111111111111111111111100000000001111111 printStringRadix: 16) dump. (2r110101010101010101010101010101111111111111111111111111111111111111111111111111111111100000000001111111 printStringRadix: 16) dump.
@ -366,7 +367,14 @@ PROCESS TESTING
## ((-2r110101010101010101010101010101111111111111111111111111111111111111111111111111111111100000000001111111 bitShift: 16r1FFFFFFFFFFFFFFFF) printStringRadix: 2) dump. ## ((-2r110101010101010101010101010101111111111111111111111111111111111111111111111111111111100000000001111111 bitShift: 16r1FFFFFFFFFFFFFFFF) printStringRadix: 2) dump.
##((-2r11111111110000000000111110000 bitShift: -31) printStringRadix: 2) dump. ##((-2r11111111110000000000111110000 bitShift: -31) printStringRadix: 2) dump.
((-536870911 bitShift: -536870912) printStringRadix: 2) dump. ##((-536870911 bitShift: -536870912) printStringRadix: 2) dump.
((-2r1111 bitShift: -3) printStringRadix: 2) dump.
((-2r11111111111111111111111111111111111111111111111111111111111111111111110001 bitShift: -1) printStringRadix: 2) dump.
((-2r11111111111111111111111111111111111111111111111111111111111111111111110001 bitShift: -2) printStringRadix: 2) dump.
((-2r11111111111111111111111111111111111111111111111111111111111111111111110001 bitShift: -3) printStringRadix: 2) dump.
((-2r11111111111111111111111111111111111111111111111111111111111111111111110001 bitShift: -200) printStringRadix: 2) dump.
((-2r1000000000000000000000000000100000000000000000000000000000000000000000000000 bitShift: -5) printStringRadix: 2) dump.
" "
FFI isNil dump. FFI isNil dump.

110
stix/lib/bigint.c
View File

@ -547,7 +547,7 @@ static void complement2_unsigned_array (const stix_liw_t* x, stix_oow_t xs, stix
for (i = 0; i < xs; i++) for (i = 0; i < xs; i++)
{ {
w = (stix_lidw_t)(~x[i]) + carry; w = (stix_lidw_t)(~x[i]) + carry;
/*w = (stix_lidw_t)(x[i] ^ STIX_TYPE_MAX(stix_liw_t)) + carry;*/ /*w = (stix_lidw_t)(x[i] ^ (~(stix_liw_t)0)) + carry;*/
carry = w >> STIX_LIW_BITS; carry = w >> STIX_LIW_BITS;
z[i] = w; z[i] = w;
} }
@ -1644,7 +1644,7 @@ stix_oop_t stix_bitandints (stix_t* stix, stix_oop_t x, stix_oop_t y)
STIX_ASSERT (carry[0] == 0); STIX_ASSERT (carry[0] == 0);
/* 2's complement on the final result */ /* 2's complement on the final result */
((stix_oop_liword_t)z)->slot[zs] = STIX_TYPE_MAX(stix_liw_t); ((stix_oop_liword_t)z)->slot[zs] = ~(stix_liw_t)0;
carry[0] = 1; carry[0] = 1;
for (i = 0; i <= zs; i++) for (i = 0; i <= zs; i++)
{ {
@ -1859,7 +1859,7 @@ stix_oop_t stix_bitorints (stix_t* stix, stix_oop_t x, stix_oop_t y)
adjust_to_negative: adjust_to_negative:
/* 2's complement on the final result */ /* 2's complement on the final result */
((stix_oop_liword_t)z)->slot[zs] = STIX_TYPE_MAX(stix_liw_t); ((stix_oop_liword_t)z)->slot[zs] = ~(stix_liw_t)0;
carry[0] = 1; carry[0] = 1;
for (i = 0; i <= zs; i++) for (i = 0; i <= zs; i++)
{ {
@ -1918,7 +1918,7 @@ stix_oop_t stix_bitorints (stix_t* stix, stix_oop_t x, stix_oop_t y)
* redundant. * redundant.
for (; i < xs; i++) for (; i < xs; i++)
{ {
((stix_oop_liword_t)z)->slot[i] = STIX_TYPE_MAX(stix_liw_t); ((stix_oop_liword_t)z)->slot[i] = ~(stix_liw_t)0;
} }
*/ */
goto adjust_to_negative; goto adjust_to_negative;
@ -2076,7 +2076,7 @@ stix_oop_t stix_bitxorints (stix_t* stix, stix_oop_t x, stix_oop_t y)
{ {
w[0] = (stix_lidw_t)((stix_liw_t)~((stix_oop_liword_t)x)->slot[i]) + carry[0]; w[0] = (stix_lidw_t)((stix_liw_t)~((stix_oop_liword_t)x)->slot[i]) + carry[0];
carry[0] = w[0] >> STIX_LIW_BITS; carry[0] = w[0] >> STIX_LIW_BITS;
((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)w[0] ^ STIX_TYPE_MAX(stix_liw_t); ((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)w[0] ^ (~(stix_liw_t)0);
} }
STIX_ASSERT (carry[0] == 0); STIX_ASSERT (carry[0] == 0);
} }
@ -2104,7 +2104,7 @@ stix_oop_t stix_bitxorints (stix_t* stix, stix_oop_t x, stix_oop_t y)
adjust_to_negative: adjust_to_negative:
/* 2's complement on the final result */ /* 2's complement on the final result */
((stix_oop_liword_t)z)->slot[zs] = STIX_TYPE_MAX(stix_liw_t); ((stix_oop_liword_t)z)->slot[zs] = ~(stix_liw_t)0;
carry = 1; carry = 1;
for (i = 0; i <= zs; i++) for (i = 0; i <= zs; i++)
{ {
@ -2134,7 +2134,7 @@ stix_oop_t stix_bitxorints (stix_t* stix, stix_oop_t x, stix_oop_t y)
/* treat the lacking part in y as all 1s */ /* treat the lacking part in y as all 1s */
for (; i < xs; i++) for (; i < xs; i++)
{ {
((stix_oop_liword_t)z)->slot[i] = ((stix_oop_liword_t)x)->slot[i] ^ STIX_TYPE_MAX(stix_liw_t); ((stix_oop_liword_t)z)->slot[i] = ((stix_oop_liword_t)x)->slot[i] ^ (~(stix_liw_t)0);
} }
goto adjust_to_negative; goto adjust_to_negative;
@ -2225,13 +2225,13 @@ stix_oop_t stix_bitinvint (stix_t* stix, stix_oop_t x)
{ {
stix_lidw_t w, carry; stix_lidw_t w, carry;
#if 0
for (i = 0; i < xs; i++) for (i = 0; i < xs; i++)
{ {
((stix_oop_liword_t)z)->slot[i] = ~((stix_oop_liword_t)x)->slot[i]; ((stix_oop_liword_t)z)->slot[i] = ~((stix_oop_liword_t)x)->slot[i];
} }
/* 2's complement on the final result */ ((stix_oop_liword_t)z)->slot[zs] = ~(stix_liw_t)0;
((stix_oop_liword_t)z)->slot[zs] = STIX_TYPE_MAX(stix_liw_t);
carry = 1; carry = 1;
for (i = 0; i <= zs; i++) for (i = 0; i <= zs; i++)
{ {
@ -2240,6 +2240,18 @@ stix_oop_t stix_bitinvint (stix_t* stix, stix_oop_t x)
((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)w; ((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)w;
} }
STIX_ASSERT (carry == 0); STIX_ASSERT (carry == 0);
#else
carry = 1;
for (i = 0; i < xs; i++)
{
w = (stix_lidw_t)(((stix_oop_liword_t)x)->slot[i]) + carry;
carry = w >> STIX_LIW_BITS;
((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)w;
}
STIX_ASSERT (i == zs);
((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)carry;
STIX_ASSERT ((carry >> STIX_LIW_BITS) == 0);
#endif
STIX_OBJ_SET_CLASS (z, stix->_large_negative_integer); STIX_OBJ_SET_CLASS (z, stix->_large_negative_integer);
} }
@ -2371,7 +2383,7 @@ stix_oop_t stix_bitshiftint (stix_t* stix, stix_oop_t x, stix_oop_t y)
{ {
stix_oop_t z; stix_oop_t z;
int sign, negx, negy; int sign, negx, negy;
stix_oow_t shift, wshift; stix_oow_t shift;
if (!is_integer(stix,x) || !is_integer(stix, y)) goto oops_einval; if (!is_integer(stix,x) || !is_integer(stix, y)) goto oops_einval;
@ -2387,9 +2399,15 @@ stix_oop_t stix_bitshiftint (stix_t* stix, stix_oop_t x, stix_oop_t y)
{ {
/* right shift */ /* right shift */
#if defined(STIX_LIMIT_OBJ_SIZE) #if defined(STIX_LIMIT_OBJ_SIZE)
/* the maximum number of bit shifts are guaranteed to be
* small enough to fit into the stix_oow_t type. so i can
* easily assume that all bits are shifted out */
STIX_ASSERT (STIX_TYPE_MAX(stix_oow_t) >= STIX_OBJ_SIZE_MAX * 8);
return (negx)? STIX_SMOOI_TO_OOP(-1): STIX_SMOOI_TO_OOP(0); return (negx)? STIX_SMOOI_TO_OOP(-1): STIX_SMOOI_TO_OOP(0);
#else #else
/* TODO: */ /* TODO: */
/* TODO: */
/* TODO: */
#endif #endif
} }
else else
@ -2397,8 +2415,9 @@ stix_oop_t stix_bitshiftint (stix_t* stix, stix_oop_t x, stix_oop_t y)
/* left shift */ /* left shift */
#if defined(STIX_LIMIT_OBJ_SIZE) #if defined(STIX_LIMIT_OBJ_SIZE)
/* the maximum number of bit shifts are guaranteed to be /* the maximum number of bit shifts are guaranteed to be
* small enough to fit into the stix_oow_t type, i can * small enough to fit into the stix_oow_t type. so i can
* simply return a failure here */ * simply return a failure here becuase it's surely too
* large after shifting */
STIX_ASSERT (STIX_TYPE_MAX(stix_oow_t) >= STIX_OBJ_SIZE_MAX * 8); STIX_ASSERT (STIX_TYPE_MAX(stix_oow_t) >= STIX_OBJ_SIZE_MAX * 8);
stix->errnum = STIX_EOOMEM; /* is it a soft failure or a hard failure? is this error code proper? */ stix->errnum = STIX_EOOMEM; /* is it a soft failure or a hard failure? is this error code proper? */
return STIX_NULL; return STIX_NULL;
@ -2449,6 +2468,8 @@ stix_oop_t stix_bitshiftint (stix_t* stix, stix_oop_t x, stix_oop_t y)
} }
else if (sign >= 1) else if (sign >= 1)
{ {
stix_oow_t wshift;
left_shift_last: left_shift_last:
wshift = shift / STIX_LIW_BITS; wshift = shift / STIX_LIW_BITS;
if (shift > wshift * STIX_LIW_BITS) wshift++; if (shift > wshift * STIX_LIW_BITS) wshift++;
@ -2462,9 +2483,70 @@ stix_oop_t stix_bitshiftint (stix_t* stix, stix_oop_t x, stix_oop_t y)
{ {
/* right shift */ /* right shift */
STIX_ASSERT (sign <= -1); STIX_ASSERT (sign <= -1);
/*TODO" */
}
if (negx)
{
stix_lidw_t w;
stix_lidw_t carry;
stix_oow_t i, xs;
xs = STIX_OBJ_GET_SIZE(x);
stix_pushtmp (stix, &x);
stix_pushtmp (stix, &y);
/* +1 for the second inversion below */
z = stix_instantiate (stix, stix->_large_negative_integer, STIX_NULL, xs + 1);
stix_poptmps (stix, 2);
if (!z) return STIX_NULL;
/* the following lines roughly for 'z = stix_bitinv (stix, x)' */
carry = 1;
for (i = 0; i < xs; i++)
{
w = (stix_lidw_t)((stix_liw_t)~((stix_oop_liword_t)x)->slot[i]) + carry;
carry = w >> STIX_LIW_BITS;
((stix_oop_liword_t)z)->slot[i] = ~(stix_liw_t)w;
}
STIX_ASSERT (carry == 0);
/* shift to the right */
rshift_unsigned_array (((stix_oop_liword_t)z)->slot, xs, shift);
/* the following lines roughly for 'z = stix_bitinv (stix, z)' */
#if 0
for (i = 0; i < xs; i++)
{
((stix_oop_liword_t)z)->slot[i] = ~((stix_oop_liword_t)z)->slot[i];
}
((stix_oop_liword_t)z)->slot[xs] = ~(stix_liw_t)0;
carry = 1;
for (i = 0; i <= xs; i++)
{
w = (stix_lidw_t)((stix_liw_t)~((stix_oop_liword_t)z)->slot[i]) + carry;
carry = w >> STIX_LIW_BITS;
((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)w;
}
STIX_ASSERT (carry == 0);
#else
carry = 1;
for (i = 0; i < xs; i++)
{
w = (stix_lidw_t)(((stix_oop_liword_t)z)->slot[i]) + carry;
carry = w >> STIX_LIW_BITS;
((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)w;
}
((stix_oop_liword_t)z)->slot[i] = (stix_liw_t)carry;
STIX_ASSERT ((carry >> STIX_LIW_BITS) == 0);
#endif
}
else
{
z = clone_bigint (stix, x, STIX_OBJ_GET_SIZE(x));
if (!z) return STIX_NULL;
rshift_unsigned_array (((stix_oop_liword_t)z)->slot, STIX_OBJ_GET_SIZE(z), shift);
}
}
return normalize_bigint(stix, z); return normalize_bigint(stix, z);
} }