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#define SLOT_E 'E'
#define SLOT_U 'U'
#define SLOT_L 'L'
#if defined DEBUG && DEBUG == 1
#include <stdio.h>
#define PRINT_DEBUG printf("%c%c%c%c\n", slot._3, slot._2, slot._1, slot._0)
#define RULE1() \
slot._3 = 'U'; \
slot._2 = 'U'; \
slot._1 = 'U'; \
slot._0 = 'U'
#define RULE2() \
slot._3 = 'E'; \
slot._2 = 'U'; \
slot._1 = 'U'; \
slot._0 = 'U'
#define RULE3() \
slot._3 = 'U'; \
slot._2 = 'U'; \
slot._1 = 'E'; \
slot._0 = 'L'
#define RULE3B() \
slot._3 = 'E'; \
slot._2 = 'E'; \
slot._1 = 'L'; \
slot._0 = 'L'
#define RULE4C() \
slot._3 = 'E'; \
slot._2 = 'E'; \
slot._1 = 'E'; \
slot._0 = 'U'
#define RULE4A() \
slot._3 = 'E'; \
slot._2 = 'L'; \
slot._1 = 'E'; \
slot._0 = 'U'
#define RULE4AD() \
slot._3 = 'U'; \
slot._2 = 'L'; \
slot._1 = 'E'; \
slot._0 = 'E'
#define RULE4CD() \
slot._3 = 'E'; \
slot._2 = 'E'; \
slot._1 = 'E'; \
slot._0 = 'E'
#endif /* DEBUG */
struct slotting_t
{
int _3;
int _2;
int _1;
int _0;
};
static inline int
number_slotted(struct slotting_t slot, int which)
{
int num = 0;
if (slot._3 == which) ++num;
if (slot._2 == which) ++num;
if (slot._1 == which) ++num;
if (slot._0 == which) ++num;
return num;
}
static inline struct slotting_t
replace_E_with(struct slotting_t slot, int which)
{
if (slot._3 == SLOT_E) slot._3 = which;
if (slot._2 == SLOT_E) slot._2 = which;
if (slot._1 == SLOT_E) slot._1 = which;
if (slot._0 == SLOT_E) slot._0 = which;
return slot;
}
struct slotting_t
determine_slotting(struct slotting_t slot)
{
int slotted_E = number_slotted(slot, SLOT_E);
/* Ebox slotting rules; Compiler Writer's Guide for the Alpha 21264, pg 69
* A.1 Rule 1 - Four of a Kind
* if all instructions are slotted U or all instructios are slotted L,
* then the classification is honored.
*/
if (slotted_E == 0)
{
return slot;
}
/* Ebox slotting rules; Compiler Writer's Guide for the Alpha 21264, pg 69-70
* A.2 Rule 2a - Three of a Kind
* if and only if three instructions are slotted U,
* then the classification is honored and the other instruction is slotted L.
* A.3 Rule 3a - Two of a Kind
* if and only if two instructions are slotted U,
* then the classification is honored and the other instructions are slotted L.
*/
if ((number_slotted(slot, SLOT_U) == 3)
|| (number_slotted(slot, SLOT_U) == 2))
{
return replace_E_with(slot, SLOT_L);
}
/* Ebox slotting rules; Compiler Writer's Guide for the Alpha 21264, pg 70
* A.2 Rule 2b - Three of a Kind
* if and only if three instructions are slotted L,
* then the classification is honored and the other instruction is slotted U.
* A.3 Rule 3b - Two of a Kind
* if and only if two instructions are slotted L,
* then the classification is honored and the other instructions are slotted U.
*/
if ((number_slotted(slot, SLOT_L) == 3)
|| (number_slotted(slot, SLOT_L) == 2))
{
return replace_E_with(slot, SLOT_U);
}
/* Ebox slotting rules; Compiler Writer's Guide for the Alpha 21264, pg 70
* A.4 Rule 4c - One of a Kind and None of a Kind
* if both instructions in the second quadword are slotted E,
* then the first is slotted L and the second slotted U.
*/
if ((slot._3 == SLOT_E) && (slot._2 == SLOT_E))
{
slot._3 = SLOT_U;
slot._2 = SLOT_L;
slotted_E -= 2;
}
if (slotted_E == 0)
{
return slot;
}
/* check low quad for single U */
if ((slot._1 == SLOT_U) != (slot._0 == SLOT_U))
{
if (slot._0 == SLOT_E)
{
slot._0 = SLOT_L;
}
else
{
slot._1 = SLOT_L;
}
--slotted_E;
}
/* check low quad for single L */
else if ((slot._1 == SLOT_L) != (slot._0 == SLOT_L))
{
if (slot._0 == SLOT_E)
{
slot._0 = SLOT_U;
}
else
{
slot._1 = SLOT_U;
}
--slotted_E;
}
if (slotted_E == 0)
{
return slot;
}
#if defined DEBUG && DEBUG == 1
PRINT_DEBUG;
#endif
/* check high quad for single U */
if ((slot._3 == SLOT_U) != (slot._2 == SLOT_U))
{
if (slot._2 == SLOT_E)
{
slot._2 = SLOT_L;
}
else if (slot._3 == SLOT_E)
{
slot._3 = SLOT_L;
}
--slotted_E;
}
/* check high quad for single L */
else if ((slot._3 == SLOT_L) != (slot._2 == SLOT_L))
{
if (slot._2 == SLOT_E)
{
slot._2 = SLOT_U;
}
else if (slot._3 == SLOT_E)
{
slot._3 = SLOT_U;
}
--slotted_E;
}
#if defined DEBUG && DEBUG == 1
PRINT_DEBUG;
#endif
/* if we reach here the only possibility is two Es in the low quad */
if (slotted_E != 0)
{
slot._1 = slot._3;
slot._0 = slot._2;
}
return slot;
}
#if defined DEBUG && DEBUG == 1
int main() {
struct slotting_t slot;
// RULE3();
// RULE3B();
// RULE4C();
RULE4A();
// RULE4AD();
// RULE4CD();
PRINT_DEBUG;
slot = determine_slotting(slot);
PRINT_DEBUG;
return 0;
}
#endif
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