From 56da36ef79a1c7ffb39836e1838084ed53dda6f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 14 Dec 2010 07:23:19 +0100
Subject: Support packing of the 'I' type in a 64-bit emulator

In many (not all) cases, the value for the 'I' type will
fit into 32 bits.
---
 erts/emulator/beam/beam_debug.c  |  6 ++++++
 erts/emulator/beam/beam_emu.c    |  1 +
 erts/emulator/beam/beam_load.c   |  5 +++++
 erts/emulator/utils/beam_makeops | 32 +++++++++++++++++++++++++++-----
 4 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/erts/emulator/beam/beam_debug.c b/erts/emulator/beam/beam_debug.c
index 9f8d338fbd..4fa9d60bca 100644
--- a/erts/emulator/beam/beam_debug.c
+++ b/erts/emulator/beam/beam_debug.c
@@ -378,6 +378,12 @@ print_op(int to, void *to_arg, int op, int size, BeamInstr* addr)
 		*ap++ = packed & BEAM_LOOSE_MASK;
 		packed >>= BEAM_LOOSE_SHIFT;
 		break;
+#ifdef ARCH_64
+	    case 'w':		/* Shift 32 steps */
+		*ap++ = packed & BEAM_WIDE_MASK;
+		packed >>= BEAM_WIDE_SHIFT;
+		break;
+#endif
 	    case 'p':
 		*sp++ = *--ap;
 		break;
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index 266b897672..bce51a001f 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -345,6 +345,7 @@ extern int count_instructions;
 #define yb(N) (*(Eterm *) (((unsigned char *)E) + (N)))
 #define fb(N) (*(double *) (((unsigned char *)&(freg[0].fd)) + (N)))
 #define Qb(N) (N)
+#define Ib(N) (N)
 #define x(N) reg[N]
 #define y(N) E[N]
 #define r(N) x##N
diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index 65cd6f91bb..8c380536ae 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -2002,6 +2002,11 @@ load_code(LoaderState* stp)
 		case '6':	/* Shift 16 steps */
 		    packed = (packed << BEAM_LOOSE_SHIFT) | code[--ci];
 		    break;
+#ifdef ARCH_64
+		case 'w':	/* Shift 32 steps */
+		    packed = (packed << BEAM_WIDE_SHIFT) | code[--ci];
+		    break;
+#endif
 		case 'p':	/* Put instruction (from stack). */
 		    code[ci++] = *--sp;
 		    break;
diff --git a/erts/emulator/utils/beam_makeops b/erts/emulator/utils/beam_makeops
index 00bddd2548..cf18ea4a92 100755
--- a/erts/emulator/utils/beam_makeops
+++ b/erts/emulator/utils/beam_makeops
@@ -513,12 +513,14 @@ sub emulator_output {
     print "#define NUM_SPECIFIC_OPS ", scalar(@op_to_name), "\n";
     print "\n";
     print "#ifdef ARCH_64\n";
+    print "#  define BEAM_WIDE_MASK 0xFFFFUL\n";
     print "#  define BEAM_LOOSE_MASK 0x1FFFUL\n";
     print "#if HALFWORD_HEAP\n";
     print "#  define BEAM_TIGHT_MASK 0x1FFCUL\n";
     print "#else\n";
     print "#  define BEAM_TIGHT_MASK 0x1FF8UL\n";
     print "#endif\n";
+    print "#  define BEAM_WIDE_SHIFT 32\n";
     print "#  define BEAM_LOOSE_SHIFT 16\n";
     print "#  define BEAM_TIGHT_SHIFT 16\n";
     print "#else\n";
@@ -956,15 +958,25 @@ sub do_pack {
     my(@args) = @_;
     my($packable_args) = 0;
     my @is_packable;		# Packability (boolean) for each argument.
+    my $wide_packing = 0;
 
     #
     # Count the number of packable arguments.  If we encounter any 's' or 'd'
     # arguments, packing is not possible.
     #
+    my $packable_types = "xytQ";
     foreach my $arg (@args) {
-	if ($arg =~ /^[xytQ]/) {
+	if ($arg =~ /^[$packable_types]/) {
 	    $packable_args++;
 	    push @is_packable, 1;
+	} elsif ($arg =~ /^I/ and $wordsize == 64 and $packable_args < 2) {
+	    $wide_packing = 1;
+	    push @is_packable, 1;
+	    if (++$packable_args == 2) {
+		# We can only pack two arguments. Turn off packing
+		# for the rest of the arguments.
+		$packable_types = "\xFF";
+	    }
 	} elsif ($arg =~ /^[sd]/) {
 	    return ('', '', @args);
 	} else {
@@ -992,9 +1004,19 @@ sub do_pack {
 	$args_per_word = 2;
     }
 
-    my(@shift) = @{$pack_shift[$args_per_word]};
-    my(@mask) = @{$pack_mask[$args_per_word]};
-    my(@pack_instr) = @{$pack_instr[$args_per_word]};
+    my @shift;
+    my @mask;
+    my @instr;
+
+    if ($wide_packing) {
+	@shift = ('0', 'BEAM_WIDE_SHIFT');
+	@mask = ('BEAM_WIDE_MASK', $WHOLE_WORD);
+	@instr = ('w', 'i');
+    } else {
+	@shift = @{$pack_shift[$args_per_word]};
+	@mask = @{$pack_mask[$args_per_word]};
+	@instr = @{$pack_instr[$args_per_word]};
+    }
 
     #
     # Now generate the packing instructions.  One complication is that
@@ -1022,7 +1044,7 @@ sub do_pack {
 		$this_size = 1;
 	    }
 
-	    $down = "$pack_instr[$ap]$down";
+	    $down = "$instr[$ap]$down";
 	    my($unpack) = &make_unpack($tmpnum, $shift[$ap], $mask[$ap]);
 	    $args[$i] = "pack:$this_size:$reg" . "b($unpack)";
 
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