Collect statistics on bytecode use in insnsb.c

We are starting to have to worry about running short on available
bytecodes, especially where we encode the operand number in the byte
code.  Thus, compile a table of bytecode usage and include as a
comment in insnsb.c.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 43 insertions, 1 deletions

diff --git a/insns.pl b/insns.pl
index 1f723dd5..66309f07 100755
--- a/insns.pl
+++ b/insns.pl
@@ -23,6 +23,8 @@ for ($m = 0; $m < 32; $m++) {
 }
 @disasm_prefixes = (@vexlist, @disasm_prefixes);
 
+@bytecode_count = (0) x 256;
+
 print STDERR "Reading insns.dat...\n";
 
 @args   = ();
@@ -134,6 +136,20 @@ if ( !defined($output) || $output eq 'b') {
     }
     print B "};\n";
 
+    print B "\n";
+    print B "/*\n";
+    print B " * Bytecode frequencies (including reuse):\n";
+    print B " *\n";
+    for ($i = 0; $i < 32; $i++) {
+	print B " *";
+	for ($j = 0; $j < 256; $j += 32) {
+	    print B " |" if ($j);
+	    printf B " %3o:%4d", $i+$j, $bytecode_count[$i+$j];
+	}
+	print B "\n";
+    }
+    print B " */\n";
+
     close B;
 }
 
@@ -262,7 +278,7 @@ if ( !defined($output) || $output eq 'i' ) {
     foreach $i (@opcodes, @opcodes_cc) {
 	print I "\tI_${i},\n";
 	$len = length($i);
-	$len++ if ( $i =~ /cc$/ );	# Condition codes can be 3 characters long
+	$len++ if ( $i =~ /cc$/ ); # Condition codes can be 3 characters long
 	$maxlen = $len if ( $len > $maxlen );
     }
     print I "\tI_none = -1\n";
@@ -299,6 +315,31 @@ if ( !defined($output) || $output eq 'n' ) {
 
 printf STDERR "Done: %d instructions\n", $insns;
 
+# Count primary bytecodes, for statistics
+sub count_bytecodes(@) {
+    my $skip = 0;
+    foreach my $bc (@_) {
+	if ($skip) {
+	    $skip--;
+	    next;
+	}
+	$bytecode_count[$bc]++;
+	if ($bc >= 01 && $bc <= 03) {
+	    $skip = $bc;
+	} elsif (($bc & ~03) == 010) {
+	    $skip = 1;
+	} elsif (($bc & ~013) == 0144) {
+	    $skip = 1;
+	} elsif ($bc == 0172) {
+	    $skip = 1;
+	} elsif ($bc >= 0260 && $bc <= 0270) {
+	    $skip = 2;
+	} elsif ($bc == 0330) {
+	    $skip = 1;
+	}
+    }
+}
+
 sub format_insn(@) {
     my ($opcode, $operands, $codes, $flags) = @_;
     my $num, $nd = 0;
@@ -336,6 +377,7 @@ sub format_insn(@) {
     @bytecode = (decodify($codes), 0);
     push(@bytecode_list, [@bytecode]);
     $codes = hexstr(@bytecode);
+    count_bytecodes(@bytecode);
 
     ("{I_$opcode, $num, {$operands}, \@\@CODES-$codes\@\@, $flags},", $nd);
 }