+enum
+ {
+ /** Maximum number of bytes to emit per line. */
+ DBEMIT_MAX_RUN = 8
+ };
+
+/** Context for the byte output chunker. */
+typedef struct
+{
+ unsigned char buffer[DBEMIT_MAX_RUN];
+ int pos;
+} DBEMITCTX;
+
+
+/** Flushes a byte chunker by writing out all in the buffer and
+ reseting.
+*/
+static void
+_dbFlush(DBEMITCTX *self)
+{
+ char line[256];
+
+ if (self->pos > 0)
+ {
+ int i;
+ sprintf(line, ".db 0x%02X", self->buffer[0]);
+
+ for (i = 1; i < self->pos; i++)
+ {
+ sprintf(line + strlen(line), ", 0x%02X", self->buffer[i]);
+ }
+ emit2(line);
+ }
+ self->pos = 0;
+}
+
+/** Write out another byte, buffering until a decent line is
+ generated.
+*/
+static void
+_dbEmit(DBEMITCTX *self, int c)
+{
+ if (self->pos == DBEMIT_MAX_RUN)
+ {
+ _dbFlush(self);
+ }
+ self->buffer[self->pos++] = c;
+}
+
+/** Context for a simple run length encoder. */
+typedef struct
+{
+ unsigned last;
+ unsigned char buffer[128];
+ int pos;
+ /** runLen may be equivalent to pos. */
+ int runLen;
+} RLECTX;
+
+enum
+ {
+ RLE_CHANGE_COST = 4,
+ RLE_MAX_BLOCK = 127
+ };
+
+/** Flush the buffer of a run length encoder by writing out the run or
+ data that it currently contains.
+*/
+static void
+_rleCommit(RLECTX *self)
+{
+ int i;
+ if (self->pos != 0)
+ {
+ DBEMITCTX db;
+ memset(&db, 0, sizeof(db));
+
+ emit2(".db %u", self->pos);
+
+ for (i = 0; i < self->pos; i++)
+ {
+ _dbEmit(&db, self->buffer[i]);
+ }
+ _dbFlush(&db);
+ }
+ /* Reset */
+ self->pos = 0;
+}
+
+/* Encoder design:
+ Can get either a run or a block of random stuff.
+ Only want to change state if a good run comes in or a run ends.
+ Detecting run end is easy.
+ Initial state?
+
+ Say initial state is in run, len zero, last zero. Then if you get a
+ few zeros then something else then a short run will be output.
+ Seems OK. While in run mode, keep counting. While in random mode,
+ keep a count of the run. If run hits margin, output all up to run,
+ restart, enter run mode.
+*/
+
+/** Add another byte into the run length encoder, flushing as
+ required. The run length encoder uses the Amiga IFF style, where
+ a block is prefixed by its run length. A positive length means
+ the next n bytes pass straight through. A negative length means
+ that the next byte is repeated -n times. A zero terminates the
+ chunks.
+*/
+static void
+_rleAppend(RLECTX *self, int c)
+{
+ int i;
+
+ if (c != self->last)
+ {
+ /* The run has stopped. See if it is worthwhile writing it out
+ as a run. Note that the random data comes in as runs of
+ length one.
+ */
+ if (self->runLen > RLE_CHANGE_COST)
+ {
+ /* Yes, worthwhile. */
+ /* Commit whatever was in the buffer. */
+ _rleCommit(self);
+ emit2(".db -%u,0x%02X", self->runLen, self->last);
+ }
+ else
+ {
+ /* Not worthwhile. Append to the end of the random list. */
+ for (i = 0; i < self->runLen; i++)
+ {
+ if (self->pos >= RLE_MAX_BLOCK)
+ {
+ /* Commit. */
+ _rleCommit(self);
+ }
+ self->buffer[self->pos++] = self->last;
+ }
+ }
+ self->runLen = 1;
+ self->last = c;
+ }
+ else
+ {
+ if (self->runLen >= RLE_MAX_BLOCK)
+ {
+ /* Commit whatever was in the buffer. */
+ _rleCommit(self);
+
+ emit2 (".db -%u,0x%02X", self->runLen, self->last);
+ self->runLen = 0;
+ }
+ self->runLen++;
+ }
+}
+
+static void
+_rleFlush(RLECTX *self)
+{
+ _rleAppend(self, -1);
+ _rleCommit(self);
+ self->pos = 0;
+ self->last = 0;
+ self->runLen = 0;
+}
+
+/** genArrayInit - Special code for initialising an array with constant
+ data.
+*/
+static void
+genArrayInit (iCode * ic)
+{
+ literalList *iLoop;
+ int ix;
+ int elementSize = 0, eIndex, i;
+ unsigned val, lastVal;
+ sym_link *type;
+ RLECTX rle;
+
+ memset(&rle, 0, sizeof(rle));
+
+ aopOp (IC_LEFT(ic), ic, FALSE, FALSE);
+
+ if (AOP_TYPE(IC_LEFT(ic)) == AOP_IMMD)
+ {
+ /* Emit the support function call and the destination address. */
+ emit2("call __initrleblock");
+ emit2(".dw %s", aopGetWord (AOP(IC_LEFT(ic)), 0));
+ }
+ else
+ {
+ wassertl (0, "Unexpected operand to genArrayInit.\n");
+ }
+
+ type = operandType(IC_LEFT(ic));
+
+ if (type && type->next)
+ {
+ elementSize = getSize(type->next);
+ }
+ else
+ {
+ wassertl (0, "Can't determine element size in genArrayInit.");
+ }
+
+ iLoop = IC_ARRAYILIST(ic);
+ lastVal = (unsigned)-1;
+
+ /* Feed all the bytes into the run length encoder which will handle
+ the actual output.
+ This works well for mixed char data, and for random int and long
+ data.
+ */
+ while (iLoop)
+ {
+ ix = iLoop->count;
+
+ if (ix != 0)
+ {
+ for (i = 0; i < ix; i++)
+ {
+ for (eIndex = 0; eIndex < elementSize; eIndex++)
+ {
+ val = (((int)iLoop->literalValue) >> (eIndex * 8)) & 0xff;
+ _rleAppend(&rle, val);
+ }
+ }
+ }
+
+ iLoop = iLoop->next;
+ }
+
+ _rleFlush(&rle);
+ /* Mark the end of the run. */
+ emit2(".db 0");
+
+ freeAsmop (IC_LEFT(ic), NULL, ic);
+}
+
projects / fw / sdcc / blobdiff