ARM: Add DynASM ARM module and encoding engine.

1 files changed, 440 insertions, 0 deletions

diff --git a/dynasm/dasm_arm.h b/dynasm/dasm_arm.h
new file mode 100644
index 00000000..3fd795b7
--- /dev/null
+++ b/dynasm/dasm_arm.h
@@ -0,0 +1,440 @@
+/*
+** DynASM ARM encoding engine.
+** Copyright (C) 2005-2011 Mike Pall. All rights reserved.
+** Released under the MIT/X license. See dynasm.lua for full copyright notice.
+*/
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define DASM_ARCH		"arm"
+
+#ifndef DASM_EXTERN
+#define DASM_EXTERN(a,b,c,d)	0
+#endif
+
+/* Action definitions. */
+enum {
+  DASM_STOP, DASM_SECTION, DASM_ESC, DASM_REL_EXT,
+  /* The following actions need a buffer position. */
+  DASM_ALIGN, DASM_REL_LG, DASM_LABEL_LG,
+  /* The following actions also have an argument. */
+  DASM_REL_PC, DASM_LABEL_PC,
+  DASM_IMM, DASM_IMM12, DASM_IMM16, DASM_IMML8, DASM_IMML12,
+  DASM__MAX
+};
+
+/* Maximum number of section buffer positions for a single dasm_put() call. */
+#define DASM_MAXSECPOS		25
+
+/* DynASM encoder status codes. Action list offset or number are or'ed in. */
+#define DASM_S_OK		0x00000000
+#define DASM_S_NOMEM		0x01000000
+#define DASM_S_PHASE		0x02000000
+#define DASM_S_MATCH_SEC	0x03000000
+#define DASM_S_RANGE_I		0x11000000
+#define DASM_S_RANGE_SEC	0x12000000
+#define DASM_S_RANGE_LG		0x13000000
+#define DASM_S_RANGE_PC		0x14000000
+#define DASM_S_RANGE_REL	0x15000000
+#define DASM_S_UNDEF_LG		0x21000000
+#define DASM_S_UNDEF_PC		0x22000000
+
+/* Macros to convert positions (8 bit section + 24 bit index). */
+#define DASM_POS2IDX(pos)	((pos)&0x00ffffff)
+#define DASM_POS2BIAS(pos)	((pos)&0xff000000)
+#define DASM_SEC2POS(sec)	((sec)<<24)
+#define DASM_POS2SEC(pos)	((pos)>>24)
+#define DASM_POS2PTR(D, pos)	(D->sections[DASM_POS2SEC(pos)].rbuf + (pos))
+
+/* Action list type. */
+typedef const unsigned int *dasm_ActList;
+
+/* Per-section structure. */
+typedef struct dasm_Section {
+  int *rbuf;		/* Biased buffer pointer (negative section bias). */
+  int *buf;		/* True buffer pointer. */
+  size_t bsize;		/* Buffer size in bytes. */
+  int pos;		/* Biased buffer position. */
+  int epos;		/* End of biased buffer position - max single put. */
+  int ofs;		/* Byte offset into section. */
+} dasm_Section;
+
+/* Core structure holding the DynASM encoding state. */
+struct dasm_State {
+  size_t psize;			/* Allocated size of this structure. */
+  dasm_ActList actionlist;	/* Current actionlist pointer. */
+  int *lglabels;		/* Local/global chain/pos ptrs. */
+  size_t lgsize;
+  int *pclabels;		/* PC label chains/pos ptrs. */
+  size_t pcsize;
+  void **globals;		/* Array of globals (bias -10). */
+  dasm_Section *section;	/* Pointer to active section. */
+  size_t codesize;		/* Total size of all code sections. */
+  int maxsection;		/* 0 <= sectionidx < maxsection. */
+  int status;			/* Status code. */
+  dasm_Section sections[1];	/* All sections. Alloc-extended. */
+};
+
+/* The size of the core structure depends on the max. number of sections. */
+#define DASM_PSZ(ms)	(sizeof(dasm_State)+(ms-1)*sizeof(dasm_Section))
+
+
+/* Initialize DynASM state. */
+void dasm_init(Dst_DECL, int maxsection)
+{
+  dasm_State *D;
+  size_t psz = 0;
+  int i;
+  Dst_REF = NULL;
+  DASM_M_GROW(Dst, struct dasm_State, Dst_REF, psz, DASM_PSZ(maxsection));
+  D = Dst_REF;
+  D->psize = psz;
+  D->lglabels = NULL;
+  D->lgsize = 0;
+  D->pclabels = NULL;
+  D->pcsize = 0;
+  D->globals = NULL;
+  D->maxsection = maxsection;
+  for (i = 0; i < maxsection; i++) {
+    D->sections[i].buf = NULL;  /* Need this for pass3. */
+    D->sections[i].rbuf = D->sections[i].buf - DASM_SEC2POS(i);
+    D->sections[i].bsize = 0;
+    D->sections[i].epos = 0;  /* Wrong, but is recalculated after resize. */
+  }
+}
+
+/* Free DynASM state. */
+void dasm_free(Dst_DECL)
+{
+  dasm_State *D = Dst_REF;
+  int i;
+  for (i = 0; i < D->maxsection; i++)
+    if (D->sections[i].buf)
+      DASM_M_FREE(Dst, D->sections[i].buf, D->sections[i].bsize);
+  if (D->pclabels) DASM_M_FREE(Dst, D->pclabels, D->pcsize);
+  if (D->lglabels) DASM_M_FREE(Dst, D->lglabels, D->lgsize);
+  DASM_M_FREE(Dst, D, D->psize);
+}
+
+/* Setup global label array. Must be called before dasm_setup(). */
+void dasm_setupglobal(Dst_DECL, void **gl, unsigned int maxgl)
+{
+  dasm_State *D = Dst_REF;
+  D->globals = gl - 10;  /* Negative bias to compensate for locals. */
+  DASM_M_GROW(Dst, int, D->lglabels, D->lgsize, (10+maxgl)*sizeof(int));
+}
+
+/* Grow PC label array. Can be called after dasm_setup(), too. */
+void dasm_growpc(Dst_DECL, unsigned int maxpc)
+{
+  dasm_State *D = Dst_REF;
+  size_t osz = D->pcsize;
+  DASM_M_GROW(Dst, int, D->pclabels, D->pcsize, maxpc*sizeof(int));
+  memset((void *)(((unsigned char *)D->pclabels)+osz), 0, D->pcsize-osz);
+}
+
+/* Setup encoder. */
+void dasm_setup(Dst_DECL, const void *actionlist)
+{
+  dasm_State *D = Dst_REF;
+  int i;
+  D->actionlist = (dasm_ActList)actionlist;
+  D->status = DASM_S_OK;
+  D->section = &D->sections[0];
+  memset((void *)D->lglabels, 0, D->lgsize);
+  if (D->pclabels) memset((void *)D->pclabels, 0, D->pcsize);
+  for (i = 0; i < D->maxsection; i++) {
+    D->sections[i].pos = DASM_SEC2POS(i);
+    D->sections[i].ofs = 0;
+  }
+}
+
+
+#ifdef DASM_CHECKS
+#define CK(x, st) \
+  do { if (!(x)) { \
+    D->status = DASM_S_##st|(p-D->actionlist-1); return; } } while (0)
+#define CKPL(kind, st) \
+  do { if ((size_t)((char *)pl-(char *)D->kind##labels) >= D->kind##size) { \
+    D->status = DASM_S_RANGE_##st|(p-D->actionlist-1); return; } } while (0)
+#else
+#define CK(x, st)	((void)0)
+#define CKPL(kind, st)	((void)0)
+#endif
+
+static int dasm_imm12(unsigned int n)
+{
+  int i;
+  for (i = 0; i < 16; i++, n = (n << 2) | (n >> 30))
+    if (n <= 255) return (int)(n + (i << 8));
+  return -1;
+}
+
+/* Pass 1: Store actions and args, link branches/labels, estimate offsets. */
+void dasm_put(Dst_DECL, int start, ...)
+{
+  va_list ap;
+  dasm_State *D = Dst_REF;
+  dasm_ActList p = D->actionlist + start;
+  dasm_Section *sec = D->section;
+  int pos = sec->pos, ofs = sec->ofs;
+  int *b;
+
+  if (pos >= sec->epos) {
+    DASM_M_GROW(Dst, int, sec->buf, sec->bsize,
+      sec->bsize + 2*DASM_MAXSECPOS*sizeof(int));
+    sec->rbuf = sec->buf - DASM_POS2BIAS(pos);
+    sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos);
+  }
+
+  b = sec->rbuf;
+  b[pos++] = start;
+
+  va_start(ap, start);
+  while (1) {
+    unsigned int ins = *p++;
+    unsigned int action = (ins >> 16);
+    if (action >= DASM__MAX) {
+      ofs += 4;
+    } else {
+      int *pl, n = action >= DASM_REL_PC ? va_arg(ap, int) : 0;
+      switch (action) {
+      case DASM_STOP: goto stop;
+      case DASM_SECTION:
+	n = (ins & 255); CK(n < D->maxsection, RANGE_SEC);
+	D->section = &D->sections[n]; goto stop;
+      case DASM_ESC: p++; ofs += 4; break;
+      case DASM_REL_EXT: break;
+      case DASM_ALIGN: ofs += (ins & 255); b[pos++] = ofs; break;
+      case DASM_REL_LG:
+	n = (ins & 2047) - 10; pl = D->lglabels + n;
+	if (n >= 0) { CKPL(lg, LG); goto putrel; }  /* Bkwd rel or global. */
+	pl += 10; n = *pl;
+	if (n < 0) n = 0;  /* Start new chain for fwd rel if label exists. */
+	goto linkrel;
+      case DASM_REL_PC:
+	pl = D->pclabels + n; CKPL(pc, PC);
+      putrel:
+	n = *pl;
+	if (n < 0) {  /* Label exists. Get label pos and store it. */
+	  b[pos] = -n;
+	} else {
+      linkrel:
+	  b[pos] = n;  /* Else link to rel chain, anchored at label. */
+	  *pl = pos;
+	}
+	pos++;
+	break;
+      case DASM_LABEL_LG:
+	pl = D->lglabels + (ins & 2047) - 10; CKPL(lg, LG); goto putlabel;
+      case DASM_LABEL_PC:
+	pl = D->pclabels + n; CKPL(pc, PC);
+      putlabel:
+	n = *pl;  /* n > 0: Collapse rel chain and replace with label pos. */
+	while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos;
+	}
+	*pl = -pos;  /* Label exists now. */
+	b[pos++] = ofs;  /* Store pass1 offset estimate. */
+	break;
+      case DASM_IMM:
+      case DASM_IMM16:
+#ifdef DASM_CHECKS
+	CK((n & ((1<<((ins>>10)&31))-1)) == 0, RANGE_I);
+	if ((ins & 0x8000))
+	  CK(((n + (1<<(((ins>>5)&31)-1)))>>((ins>>5)&31)) == 0, RANGE_I);
+	else
+	  CK((n>>((ins>>5)&31)) == 0, RANGE_I);
+#endif
+	b[pos++] = n;
+	break;
+      case DASM_IMML8:
+      case DASM_IMML12:
+	CK(n >= 0 ? ((n>>((ins>>5)&31)) == 0) :
+		    (((-n)>>((ins>>5)&31)) == 0), RANGE_I);
+	b[pos++] = n;
+	break;
+      case DASM_IMM12:
+	CK(dasm_imm12((unsigned int)n) != -1, RANGE_I);
+	b[pos++] = n;
+	break;
+      }
+    }
+  }
+stop:
+  va_end(ap);
+  sec->pos = pos;
+  sec->ofs = ofs;
+}
+#undef CK
+
+/* Pass 2: Link sections, shrink aligns, fix label offsets. */
+int dasm_link(Dst_DECL, size_t *szp)
+{
+  dasm_State *D = Dst_REF;
+  int secnum;
+  int ofs = 0;
+
+#ifdef DASM_CHECKS
+  *szp = 0;
+  if (D->status != DASM_S_OK) return D->status;
+  {
+    int pc;
+    for (pc = 0; pc*sizeof(int) < D->pcsize; pc++)
+      if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc;
+  }
+#endif
+
+  { /* Handle globals not defined in this translation unit. */
+    int idx;
+    for (idx = 20; idx*sizeof(int) < D->lgsize; idx++) {
+      int n = D->lglabels[idx];
+      /* Undefined label: Collapse rel chain and replace with marker (< 0). */
+      while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; }
+    }
+  }
+
+  /* Combine all code sections. No support for data sections (yet). */
+  for (secnum = 0; secnum < D->maxsection; secnum++) {
+    dasm_Section *sec = D->sections + secnum;
+    int *b = sec->rbuf;
+    int pos = DASM_SEC2POS(secnum);
+    int lastpos = sec->pos;
+
+    while (pos != lastpos) {
+      dasm_ActList p = D->actionlist + b[pos++];
+      while (1) {
+	unsigned int ins = *p++;
+	unsigned int action = (ins >> 16);
+	switch (action) {
+	case DASM_STOP: case DASM_SECTION: goto stop;
+	case DASM_ESC: p++; break;
+	case DASM_REL_EXT: break;
+	case DASM_ALIGN: ofs -= (b[pos++] + ofs) & (ins & 255); break;
+	case DASM_REL_LG: case DASM_REL_PC: pos++; break;
+	case DASM_LABEL_LG: case DASM_LABEL_PC: b[pos++] += ofs; break;
+	case DASM_IMM: case DASM_IMM12: case DASM_IMM16:
+	case DASM_IMML8: case DASM_IMML12: pos++; break;
+	}
+      }
+      stop: (void)0;
+    }
+    ofs += sec->ofs;  /* Next section starts right after current section. */
+  }
+
+  D->codesize = ofs;  /* Total size of all code sections */
+  *szp = ofs;
+  return DASM_S_OK;
+}
+
+#ifdef DASM_CHECKS
+#define CK(x, st) \
+  do { if (!(x)) return DASM_S_##st|(p-D->actionlist-1); } while (0)
+#else
+#define CK(x, st)	((void)0)
+#endif
+
+/* Pass 3: Encode sections. */
+int dasm_encode(Dst_DECL, void *buffer)
+{
+  dasm_State *D = Dst_REF;
+  char *base = (char *)buffer;
+  unsigned int *cp = (unsigned int *)buffer;
+  int secnum;
+
+  /* Encode all code sections. No support for data sections (yet). */
+  for (secnum = 0; secnum < D->maxsection; secnum++) {
+    dasm_Section *sec = D->sections + secnum;
+    int *b = sec->buf;
+    int *endb = sec->rbuf + sec->pos;
+
+    while (b != endb) {
+      dasm_ActList p = D->actionlist + *b++;
+      while (1) {
+	unsigned int ins = *p++;
+	unsigned int action = (ins >> 16);
+	int n = (action >= DASM_ALIGN && action < DASM__MAX) ? *b++ : 0;
+	switch (action) {
+	case DASM_STOP: case DASM_SECTION: goto stop;
+	case DASM_ESC: *cp++ = *p++; break;
+	case DASM_REL_EXT:
+	  n = DASM_EXTERN(Dst, (unsigned char *)cp, (ins & 2047), 1);
+	  goto patchrel;
+	case DASM_ALIGN:
+	  ins &= 255; while ((((char *)cp - base) & ins)) *cp++ = 0xe1a00000;
+	  break;
+	case DASM_REL_LG:
+	  CK(n >= 0, UNDEF_LG);
+	case DASM_REL_PC:
+	  CK(n >= 0, UNDEF_PC);
+	  n = *DASM_POS2PTR(D, n) - (int)((char *)cp - base);
+	patchrel:
+	  CK((n & 3) == 0 && ((n-4+0x02000000) >> 26) == 0, RANGE_REL);
+	  cp[-1] |= (((n-4) >> 2) & 0x00ffffff);
+	  break;
+	case DASM_LABEL_LG:
+	  ins &= 2047; if (ins >= 20) D->globals[ins-10] = (void *)(base + n);
+	  break;
+	case DASM_LABEL_PC: break;
+	case DASM_IMM:
+	  cp[-1] |= ((n>>((ins>>10)&31)) & ((1<<((ins>>5)&31))-1)) << (ins&31);
+	  break;
+	case DASM_IMM12:
+	  cp[-1] |= dasm_imm12((unsigned int)n);
+	  break;
+	case DASM_IMM16:
+	  cp[-1] |= ((n & 0xf000) << 4) | (n & 0x0fff);
+	  break;
+	case DASM_IMML8:
+	  cp[-1] |= n >= 0 ? (0x00800000 | (n & 0x0f) | ((n & 0xf0) << 4)) :
+			     ((-n & 0x0f) | ((-n & 0xf0) << 4));
+	  break;
+	case DASM_IMML12:
+	  cp[-1] |= n >= 0 ? (0x00800000 | n) : (-n);
+	  break;
+	default: *cp++ = ins; break;
+	}
+      }
+      stop: (void)0;
+    }
+  }
+
+  if (base + D->codesize != (char *)cp)  /* Check for phase errors. */
+    return DASM_S_PHASE;
+  return DASM_S_OK;
+}
+#undef CK
+
+/* Get PC label offset. */
+int dasm_getpclabel(Dst_DECL, unsigned int pc)
+{
+  dasm_State *D = Dst_REF;
+  if (pc*sizeof(int) < D->pcsize) {
+    int pos = D->pclabels[pc];
+    if (pos < 0) return *DASM_POS2PTR(D, -pos);
+    if (pos > 0) return -1;  /* Undefined. */
+  }
+  return -2;  /* Unused or out of range. */
+}
+
+#ifdef DASM_CHECKS
+/* Optional sanity checker to call between isolated encoding steps. */
+int dasm_checkstep(Dst_DECL, int secmatch)
+{
+  dasm_State *D = Dst_REF;
+  if (D->status == DASM_S_OK) {
+    int i;
+    for (i = 1; i <= 9; i++) {
+      if (D->lglabels[i] > 0) { D->status = DASM_S_UNDEF_LG|i; break; }
+      D->lglabels[i] = 0;
+    }
+  }
+  if (D->status == DASM_S_OK && secmatch >= 0 &&
+      D->section != &D->sections[secmatch])
+    D->status = DASM_S_MATCH_SEC|(D->section-D->sections);
+  return D->status;
+}
+#endif
+