Changeset 46957 in vbox for trunk/src/VBox/VMM/VMMAll

Timestamp:

Jul 4, 2013 2:05:41 AM (12 years ago)

Author:

vboxsync

Message:

check for DIV overflow, fixing DIV/0 checks. IDIV overflow/underflow is still on the todo.

File:

• trunk/src/VBox/VMM/VMMAll/IEMAllAImpl.asm (modified) (10 diffs)

trunk/src/VBox/VMM/VMMAll/IEMAllAImpl.asm

@@ -1322 +1322 @@
 ; @param        2       The modified flags.
 ; @param        3       The undefined flags.
+; @param        4       1 if signed, 0 if unsigned.
 ;
 ; Makes ASSUMPTIONS about A0, A1, A2, A3, T0 and T1 assignments.
 ;
-%macro IEMIMPL_DIV_OP 3
+%macro IEMIMPL_DIV_OP 4
 BEGINCODE
 BEGINPROC_FASTCALL iemAImpl_ %+ %1 %+ _u8, 12
@@ -1332 +1333 @@
         test    A1_8, A1_8
         jz      .div_zero
-        ;; @todo test for overflow
+ %if %4 == 0
+        mov     ax, [A0]
+        cmp     ah, A1_8
+        jae     .div_overflow
+ %else
+        js      .divisor_negative
+.divisor_positive:
+        mov     ax, [A0]
+        test    ax, ax
+        js      .divisor_positive_dividend_negative
+
+.both_positive:
+        shl     ax, 1
+        cmp     ah, A1_8
+        jae     .div_overflow
+        jmp     .div_no_overflow
+.both_negative:
+        neg     ax
+        shl     ax, 1
+        mov     al, A1_8
+        neg     al
+        cmp     ah, al
+        jae     .div_overflow
+        jmp     .div_no_overflow
+
+.divisor_positive_dividend_negative:
+        jmp     .div_no_overflow
+.divisor_negative:
+        test    ax, ax
+        js      .both_negative
+.divisor_negative_dividend_positive:
+        jmp     .div_no_overflow
+.div_no_overflow:
+ %endif
 
         IEM_MAYBE_LOAD_FLAGS A2, %2, %3
@@ -1345 +1379 @@
 
 .div_zero:
+.div_overflow:
         mov     eax, -1
         jmp     .return
@@ -1352 +1387 @@
         PROLOGUE_4_ARGS
 
-        test    A1_16, A1_16
+        test    A2_16, A2_16
         jz      .div_zero
-        ;; @todo test for overflow
+ %if %4 == 0
+        cmp     [A1], A2_16
+        jae     .div_overflow
+ %else
+ ;; @todo idiv  overflow checking.
+ %endif
 
         IEM_MAYBE_LOAD_FLAGS A3, %2, %3
@@ -1379 +1419 @@
 
 .div_zero:
+.div_overflow:
         mov     eax, -1
         jmp     .return
@@ -1386 +1427 @@
         PROLOGUE_4_ARGS
 
-        test    A1_32, A1_32
+        test    A2_32, A2_32
         jz      .div_zero
-        ;; @todo test for overflow
+ %if %4 == 0
+        cmp     [A1], A2_32
+        jae     .div_overflow
+ %else
+  ;; @todo idiv  overflow checking.
+ %endif
 
         IEM_MAYBE_LOAD_FLAGS A3, %2, %3
@@ -1414 +1460 @@
 
 .div_zero:
+.div_overflow:
         mov     eax, -1
         jmp     .return
@@ -1422 +1469 @@
         PROLOGUE_4_ARGS
 
-        test    A1, A1
+        test    A2, A2
         jz      .div_zero
-        ;; @todo test for overflow
+ %if %4 == 0
+        cmp     [A1], A2
+        jae     .div_overflow
+ %else
+  ;; @todo idiv  overflow checking.
+ %endif
 
         IEM_MAYBE_LOAD_FLAGS A3, %2, %3
@@ -1450 +1502 @@
 
 .div_zero:
+.div_overflow:
         mov     eax, -1
         jmp     .return
@@ -1462 +1515 @@
 %endmacro
 
-IEMIMPL_DIV_OP div,  0, (X86_EFL_OF | X86_EFL_SF | X86_EFL_ZF | X86_EFL_AF | X86_EFL_PF | X86_EFL_CF)
-IEMIMPL_DIV_OP idiv, 0, (X86_EFL_OF | X86_EFL_SF | X86_EFL_ZF | X86_EFL_AF | X86_EFL_PF | X86_EFL_CF)
+IEMIMPL_DIV_OP div,  0, (X86_EFL_OF | X86_EFL_SF | X86_EFL_ZF | X86_EFL_AF | X86_EFL_PF | X86_EFL_CF), 0
+IEMIMPL_DIV_OP idiv, 0, (X86_EFL_OF | X86_EFL_SF | X86_EFL_ZF | X86_EFL_AF | X86_EFL_PF | X86_EFL_CF), 1