decoder updates

[palacios.git] / palacios / src / palacios / vmm_decoder.c

diff --git a/palacios/src/palacios/vmm_decoder.c b/palacios/src/palacios/vmm_decoder.c
index 1d9e178..676fd6d 100644 (file)
--- a/palacios/src/palacios/vmm_decoder.c
+++ b/palacios/src/palacios/vmm_decoder.c
@@ -24,9 +24,11 @@
 
 
 
-void v3_get_prefixes(uchar_t * instr, struct x86_prefixes * prefixes) {
+uint8_t v3_get_prefixes(uint8_t * instr, struct x86_prefixes * prefixes) {
+    uint8_t * instr_cursor = instr;
+
     while (1) {
-       switch (*instr) {
+       switch (*instr_cursor) {
            case 0xF0:      // lock
                prefixes->lock = 1;
                break;
@@ -42,7 +44,7 @@ void v3_get_prefixes(uchar_t * instr, struct x86_prefixes * prefixes) {
                prefixes->repz = 1; 
                break;
 
-           case 0x2E:      // CS override or Branch hint not taken (with Jcc instrs)
+           case 0x2E:      // CS override or Branch hint not taken (with Jcc instr_cursors)
                prefixes->cs_override = 1;
                prefixes->br_not_taken = 1;
                break;
@@ -51,7 +53,7 @@ void v3_get_prefixes(uchar_t * instr, struct x86_prefixes * prefixes) {
                prefixes->ss_override = 1;
                break;
 
-           case 0x3E:      // DS override or Branch hint taken (with Jcc instrs)
+           case 0x3E:      // DS override or Branch hint taken (with Jcc instr_cursors)
                prefixes->ds_override = 1;
                prefixes->br_taken = 1;
                break;
@@ -77,12 +79,11 @@ void v3_get_prefixes(uchar_t * instr, struct x86_prefixes * prefixes) {
                break;
 
            default:
-               return;
+               return (instr_cursor - instr);
        }
 
-       instr++;
+       instr_cursor++;
     }
-
 }
 
 void v3_strip_rep_prefix(uchar_t * instr, int length) {