DynASM update from upstream capr/LuaJIT:v2.1-dynasm-luamode

src/dasm.lua

@@ -1,12 +1,12 @@
 
---binding to the DynASM encoding engine.
+--Binding to the DynASM encoding engine.
 --Written by Cosmin Apreutesei. Public Domain.
 
 local ffi = require'ffi'
 local bit = require'bit'
 local arch = ffi.arch
 if arch == 'x64' then arch = 'x86' end --same linker for x64
-local C = ffi.C
+local C = ffi.load('dasm_'..arch)
 local M = {C = C}
 
 M._VERSION = 10400

src/dasm_x64.lua

@@ -9,10 +9,11 @@
 ------------------------------------------------------------------------------
 
 --unload dasm_x86 if it's already loaded.
+if not package then package = {loaded = {}} end --for compat. with minilua
 local dasm_x86 = package.loaded.dasm_x86
 package.loaded.dasm_x86 = nil
 
-rawset(_G, 'x64', true) -- Using a global is an ugly, but effective solution.
+x64 = true -- Using a global is an ugly, but effective solution.
 local dasm_x64 = require("dasm_x86")
 
 package.loaded.dasm_x86 = dasm_x86 --put it back

src/dasm_x86.c

@@ -1,4 +1,10 @@
-#define DASM_CHECKS
+/*
+  Encoding engine to use with dasm.lua.
+
+  Compile with:
+
+    gcc dasm_x86.c -DDASM_CHECKS -shared -s -o dasm_x86.so
+*/
 
 #include "dasm_extern.h"
 #include "dasm_proto.h"

src/dasm_x86.h

@@ -170,7 +170,7 @@ void dasm_put(Dst_DECL, int start, ...)
   dasm_State *D = Dst_REF;
   dasm_ActList p = D->actionlist + start;
   dasm_Section *sec = D->section;
-  int pos = sec->pos, ofs = sec->ofs, mrm = 4;
+  int pos = sec->pos, ofs = sec->ofs, mrm = -1;
   int *b;
 
   if (pos >= sec->epos) {
@@ -193,7 +193,7 @@ void dasm_put(Dst_DECL, int start, ...)
       b[pos++] = n;
       switch (action) {
       case DASM_DISP:
-	if (n == 0) { if ((mrm&7) == 4) mrm = p[-2]; if ((mrm&7) != 5) break; }
+	if (n == 0) { if (mrm < 0) mrm = p[-2]; if ((mrm&7) != 5) break; }
       case DASM_IMM_DB: if (((n+128)&-256) == 0) goto ob;
       case DASM_REL_A: /* Assumes ptrdiff_t is int. !x64 */
       case DASM_IMM_D: ofs += 4; break;
@@ -203,10 +203,17 @@ void dasm_put(Dst_DECL, int start, ...)
       case DASM_IMM_W: CK((n&-65536) == 0, RANGE_I); ofs += 2; break;
       case DASM_SPACE: p++; ofs += n; break;
       case DASM_SETLABEL: b[pos-2] = -0x40000000; break;  /* Neg. label ofs. */
-      case DASM_VREG: CK((n&-8) == 0 && (n != 4 || (*p&1) == 0), RANGE_VREG);
-	if (*p++ == 1 && *p == DASM_DISP) mrm = n; continue;
+      case DASM_VREG: CK((n&-16) == 0 && (n != 4 || (*p>>5) != 2), RANGE_VREG);
+	if (*p < 0x40 && p[1] == DASM_DISP) mrm = n;
+	if (*p < 0x20 && (n&7) == 4) ofs++;
+	switch ((*p++ >> 3) & 3) {
+	case 3: n |= b[pos-3];
+	case 2: n |= b[pos-2];
+	case 1: if (n <= 7) { b[pos-1] |= 0x10; ofs--; }
+	}
+	continue;
       }
-      mrm = 4;
+      mrm = -1;
     } else {
       int *pl, n;
       switch (action) {
@@ -393,7 +400,22 @@ int dasm_encode(Dst_DECL, void *buffer)
 	case DASM_IMM_W: dasmw(n); break;
 	case DASM_VREG: {
 	  int t = *p++;
-	  if (t >= 5) n <<= 4; else if (t >= 2) n <<= 3;
+	  unsigned char *ex = cp - (t&7);
+	  if ((n & 8) && t < 0xa0) {
+	    if (*ex & 0x80) ex[1] ^= 0x20 << (t>>6); else *ex ^= 1 << (t>>6);
+	    n &= 7;
+	  } else if (n & 0x10) {
+	    if (*ex & 0x80) {
+	      *ex = 0xc5; ex[1] = (ex[1] & 0x80) | ex[2]; ex += 2;
+	    }
+	    while (++ex < cp) ex[-1] = *ex;
+	    if (mark) mark--;
+	    cp--;
+	    n &= 7;
+	  }
+	  if (t >= 0xc0) n <<= 4;
+	  else if (t >= 0x40) n <<= 3;
+	  else if (n == 4 && t < 0x20) { cp[-1] ^= n; *cp++ = 0x20; }
 	  cp[-1] ^= n;
 	  break;
 	}