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master
Přemysl Janouch 3 years ago
parent
commit
290e7087bb
Signed by: Přemysl Janouch <p.janouch@gmail.com> GPG Key ID: B715679E3A361BE6
1 changed files with 17 additions and 20 deletions
  1. +17
    -20
      bfc-amd64-linux.c

+ 17
- 20
bfc-amd64-linux.c View File

@@ -163,6 +163,19 @@ optimize_assignment (struct instruction *irb, size_t irb_len)
return out;
}

// Add the offset of the LEFT/RIGHT instruction to the accumulator
static bool
add_direction_offset (struct instruction *irb, intptr_t *acc)
{
if (irb->cmd == RIGHT)
*acc += irb->arg;
else if (irb->cmd == LEFT)
*acc -= (intptr_t) irb->arg;
else
return false;
return true;
}

// Add offsets to INC/DEC/SET stuck between LEFT/RIGHT
// and compress the LEFT/RIGHT sequences
static size_t
@@ -172,11 +185,7 @@ optimize_offseted_inc_dec (struct instruction *irb, size_t irb_len)
for (in = 0, out = 0; in < irb_len; in++, out++)
{
intptr_t dir = 0;
if (irb[in].cmd == RIGHT)
dir = irb[in].arg;
else if (irb[in].cmd == LEFT)
dir = -(intptr_t) irb[in].arg;
else
if (!add_direction_offset (&irb[in], &dir))
{
irb[out] = irb[in];
continue;
@@ -187,15 +196,9 @@ optimize_offseted_inc_dec (struct instruction *irb, size_t irb_len)
// An immediate offset has its limits on x86-64
if (dir < INT8_MIN || dir > INT8_MAX)
break;

intptr_t diff;
if (irb[in + 2].cmd == RIGHT)
diff = irb[in + 2].arg;
else if (irb[in + 2].cmd == LEFT)
diff = -(intptr_t) irb[in + 2].arg;
else
intptr_t diff = 0;
if (!add_direction_offset (&irb[in + 2], &diff))
break;

int cmd = irb[in + 1].cmd;
if (cmd != INC && cmd != DEC && cmd != SET)
break;
@@ -209,14 +212,8 @@ optimize_offseted_inc_dec (struct instruction *irb, size_t irb_len)
}

for (; in + 1 < irb_len; in++)
{
if (irb[in + 1].cmd == RIGHT)
dir += irb[in + 1].arg;
else if (irb[in + 1].cmd == LEFT)
dir -= (intptr_t) irb[in + 1].arg;
else
if (!add_direction_offset (&irb[in + 1], &dir))
break;
}

if (!dir)
out--;

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