Changeset 47138 in vbox for trunk/src/VBox/VMM/VMMAll

Timestamp:

Jul 14, 2013 6:05:53 PM (12 years ago)

Author:

vboxsync

Message:

IEM: idiv and div missing bits and fixes.

Location:

trunk/src/VBox/VMM/VMMAll

Files:

• IEMAll.cpp (modified) (1 diff)
• IEMAllAImpl.asm (modified) (5 diffs)
• IEMAllInstructions.cpp.h (modified) (2 diffs)

trunk/src/VBox/VMM/VMMAll/IEMAll.cpp

@@ -6755 +6755 @@
 #define IEM_MC_CALL_VOID_AIMPL_3(a_pfn, a0, a1, a2)       (a_pfn)((a0), (a1), (a2))
 #define IEM_MC_CALL_VOID_AIMPL_4(a_pfn, a0, a1, a2, a3)   (a_pfn)((a0), (a1), (a2), (a3))
+#define IEM_MC_CALL_AIMPL_3(a_rc, a_pfn, a0, a1, a2)      (a_rc) = (a_pfn)((a0), (a1), (a2))
 #define IEM_MC_CALL_AIMPL_4(a_rc, a_pfn, a0, a1, a2, a3)  (a_rc) = (a_pfn)((a0), (a1), (a2), (a3))
 

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

@@ -1392 +1392 @@
         PROLOGUE_4_ARGS
 
+        ; div by chainsaw check.
         test    A2_16, A2_16
         jz      .div_zero
+
+        ; Overflow check - unsigned division is simple to verify, haven't
+        ; found a simple way to check signed division yet unfortunately.
  %if %4 == 0
         cmp     [A1], A2_16
         jae     .div_overflow
  %else
- ;; @todo idiv  overflow checking.
+        mov     T0_16, [A1]
+        shl     T0_32, 16
+        mov     T0_16, [A0]              ; T0 = dividend
+        mov     T1, A2                   ; T1 = divisor
+        test    T1_16, T1_16
+        js      .divisor_negative
+        test    T0_32, T0_32
+        jns     .both_positive
+        neg     T0_32
+.one_of_each:                           ; OK range is 2^(result-with - 1) + (divisor - 1).
+        push    T0                      ; Start off like unsigned below.
+        shr     T0_32, 15
+        cmp     T0_16, T1_16
+        pop     T0
+        jb      .div_no_overflow
+        ja      .div_overflow
+        and     T0_16, 0x7fff           ; Special case for covering (divisor - 1).
+        cmp     T0_16, T1_16
+        jae     .div_overflow
+        jmp     .div_no_overflow
+
+.divisor_negative:
+        neg     T1_16
+        test    T0_32, T0_32
+        jns     .one_of_each
+        neg     T0_32
+.both_positive:                         ; Same as unsigned shifted by sign indicator bit.
+        shr     T0_32, 15
+        cmp     T0_16, T1_16
+        jae     .div_overflow
+.div_no_overflow:
  %endif
 
@@ -1432 +1466 @@
         PROLOGUE_4_ARGS
 
+        ; div by chainsaw check.
         test    A2_32, A2_32
         jz      .div_zero
+
+        ; Overflow check - unsigned division is simple to verify, haven't
+        ; found a simple way to check signed division yet unfortunately.
  %if %4 == 0
         cmp     [A1], A2_32
         jae     .div_overflow
  %else
-  ;; @todo idiv  overflow checking.
+        push    A2                      ; save A2 so we modify it (we out of regs on x86).
+        mov     T0_32, [A0]             ; T0 = dividend low
+        mov     T1_32, [A1]             ; T1 = dividend high
+        test    A2_32, A2_32
+        js      .divisor_negative
+        test    T1_32, T1_32
+        jns     .both_positive
+        neg     T0_32
+        neg     T1_32
+.one_of_each:                           ; OK range is 2^(result-with - 1) + (divisor - 1).
+        push    T0                      ; Start off like unsigned below.
+        shl     T1_32, 1
+        shr     T0_32, 31
+        or      T1_32, T0_32
+        cmp     T1_32, A2_32
+        pop     T0
+        jb      .div_no_overflow
+        ja      .div_overflow
+        and     T0_32, 0x7fffffff       ; Special case for covering (divisor - 1).
+        cmp     T0_32, A2_32
+        jae     .div_overflow
+        jmp     .div_no_overflow
+
+.divisor_negative:
+        neg     A2_32
+        test    T1_32, T1_32
+        jns     .one_of_each
+        neg     T0_32
+        neg     T1_32
+.both_positive:                         ; Same as unsigned shifted by sign indicator bit.
+        shl     T1_32, 1
+        shr     T0_32, 31
+        or      T1_32, T0_32
+        cmp     T1_32, A2_32
+        jae     .div_overflow
+.div_no_overflow:
+        pop     A2
  %endif
 
@@ -1464 +1538 @@
         EPILOGUE_4_ARGS
 
+.div_overflow:
+ %if %4 != 0
+        pop     A2
+ %endif
 .div_zero:
-.div_overflow:
         mov     eax, -1
         jmp     .return
@@ -1480 +1557 @@
         jae     .div_overflow
  %else
-  ;; @todo idiv  overflow checking.
+        push    A2                      ; save A2 so we modify it (we out of regs on x86).
+        mov     T0, [A0]                ; T0 = dividend low
+        mov     T1, [A1]                ; T1 = dividend high
+        test    A2, A2
+        js      .divisor_negative
+        test    T1, T1
+        jns     .both_positive
+        neg     T0
+        neg     T1
+.one_of_each:                           ; OK range is 2^(result-with - 1) + (divisor - 1).
+        push    T0                      ; Start off like unsigned below.
+        shl     T1, 1
+        shr     T0, 63
+        or      T1, T0
+        cmp     T1, A2
+        pop     T0
+        jb      .div_no_overflow
+        ja      .div_overflow
+        mov     T1, 0x7fffffffffffffff
+        and     T0, T1                  ; Special case for covering (divisor - 1).
+        cmp     T0, A2
+        jae     .div_overflow
+        jmp     .div_no_overflow
+
+.divisor_negative:
+        neg     A2
+        test    T1, T1
+        jns     .one_of_each
+        neg     T0
+        neg     T1
+.both_positive:                         ; Same as unsigned shifted by sign indicator bit.
+        shl     T1, 1
+        shr     T0, 63
+        or      T1, T0
+        cmp     T1, A2
+        jae     .div_overflow
+.div_no_overflow:
+        pop     A2
  %endif
 
@@ -1506 +1620 @@
         EPILOGUE_4_ARGS_EX 12
 
+.div_overflow:
+ %if %4 != 0
+        pop     A2
+ %endif
 .div_zero:
-.div_overflow:
         mov     eax, -1
         jmp     .return

trunk/src/VBox/VMM/VMMAll/IEMAllInstructions.cpp.h

@@ -15067 +15067 @@
         /* register access */
         IEMOP_HLP_NO_LOCK_PREFIX();
-        IEM_MC_BEGIN(3, 0);
-        IEM_MC_ARG(uint16_t *,      pu16AX,     0);
-        IEM_MC_ARG(uint8_t,         u8Value,    1);
-        IEM_MC_ARG(uint32_t *,      pEFlags,    2);
-        IEM_MC_FETCH_GREG_U8(u8Value, (bRm & X86_MODRM_RM_MASK) | pIemCpu->uRexB);
-        IEM_MC_REF_GREG_U16(pu16AX, X86_GREG_xAX);
-        IEM_MC_REF_EFLAGS(pEFlags);
-        IEM_MC_CALL_VOID_AIMPL_3(pfnU8, pu16AX, u8Value, pEFlags);
-        IEM_MC_ADVANCE_RIP();
-        IEM_MC_END();
-    }
-    else
-    {
-        /* memory access. */
-        IEMOP_HLP_NO_LOCK_PREFIX(); /** @todo should probably not be raised until we've fetched all the opcode bytes? */
-
         IEM_MC_BEGIN(3, 1);
         IEM_MC_ARG(uint16_t *,      pu16AX,     0);
         IEM_MC_ARG(uint8_t,         u8Value,    1);
         IEM_MC_ARG(uint32_t *,      pEFlags,    2);
+        IEM_MC_LOCAL(int32_t,       rc);
+
+        IEM_MC_FETCH_GREG_U8(u8Value, (bRm & X86_MODRM_RM_MASK) | pIemCpu->uRexB);
+        IEM_MC_REF_GREG_U16(pu16AX, X86_GREG_xAX);
+        IEM_MC_REF_EFLAGS(pEFlags);
+        IEM_MC_CALL_AIMPL_3(rc, pfnU8, pu16AX, u8Value, pEFlags);
+        IEM_MC_IF_LOCAL_IS_Z(rc) {
+            IEM_MC_ADVANCE_RIP();
+        } IEM_MC_ELSE() {
+            IEM_MC_RAISE_DIVIDE_ERROR();
+        } IEM_MC_ENDIF();
+
+        IEM_MC_END();
+    }
+    else
+    {
+        /* memory access. */
+        IEMOP_HLP_NO_LOCK_PREFIX(); /** @todo should probably not be raised until we've fetched all the opcode bytes? */
+
+        IEM_MC_BEGIN(3, 2);
+        IEM_MC_ARG(uint16_t *,      pu16AX,     0);
+        IEM_MC_ARG(uint8_t,         u8Value,    1);
+        IEM_MC_ARG(uint32_t *,      pEFlags,    2);
         IEM_MC_LOCAL(RTGCPTR, GCPtrEffDst);
+        IEM_MC_LOCAL(int32_t,       rc);
 
         IEM_MC_CALC_RM_EFF_ADDR(GCPtrEffDst, bRm, 0);
@@ -15093 +15101 @@
         IEM_MC_REF_GREG_U16(pu16AX, X86_GREG_xAX);
         IEM_MC_REF_EFLAGS(pEFlags);
-        IEM_MC_CALL_VOID_AIMPL_3(pfnU8, pu16AX, u8Value, pEFlags);
-
-        IEM_MC_ADVANCE_RIP();
+        IEM_MC_CALL_AIMPL_3(rc, pfnU8, pu16AX, u8Value, pEFlags);
+        IEM_MC_IF_LOCAL_IS_Z(rc) {
+            IEM_MC_ADVANCE_RIP();
+        } IEM_MC_ELSE() {
+            IEM_MC_RAISE_DIVIDE_ERROR();
+        } IEM_MC_ENDIF();
+
         IEM_MC_END();
     }