finally calculation of UInt64_Mul is correct

OlimilO1402 · Mar 2, 2022 · da83c3c · da83c3c
1 parent 869d07e
commit da83c3c
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Showing 2 changed files with 16 additions and 15 deletions.
diff --git a/Forms/Form1.frm b/Forms/Form1.frm
@@ -353,17 +353,16 @@ Sub TestDll()
 
     d = UInt64_Mul(c1, c2)
     Debug_Print VarType(d) & " " & CStr(d) '14 121932631112635269
-
-    '628239210217683
-    '41419963890366
-
-    c1 = 214748.3647 '1234.5678 '62823921021.7683
-    c2 = 214748.3647 '4141996389.0366
-    '2147483647*2147483647=4611686014132420609
-
+        
+    '     2147483647 *     2147483647 =           4611686014132420609
+    'c1 = 214748.3647
+    'c2 = 214748.3647
+
+    '628239210217683 * 41419963890366 = 26021645401728484450406541978
+    c1 = 62823921021.7683
+    c2 = 4141996389.0366
     d = UInt64_Mul(c1, c2)
-    Debug_Print VarType(d) & " " & CStr(d) '14 26021645401728484450406541978
-                                              '
+    Debug_Print VarType(d) & " " & CStr(d)
 
     s = Space(20): UInt64_ToHex cret, StrPtr(s)
     Debug_Print Trim0(s)

diff --git a/UnsignedOpsDll/UnsignedOps.asm b/UnsignedOpsDll/UnsignedOps.asm
@@ -351,9 +351,9 @@ UInt64_Sub endp
 ;                ByVal V1 As Currency, ByVal V2 As Currency, ByVal pDec_out As LongPtr
 UInt64_Mul proc
     
-	;int 3
-	
-	; 1. prepare Variant as type Decimal
+    ;int 3
+    
+    ; 1. prepare Variant as type Decimal
     mov   edi    , [esp+20] ; copy the pointer to a Variant from stack to register EDI
     mov    dx    ,      14  ; copy the vartype-word for decimal it is 14 = &HE to the register dx	
     mov  [edi+ 0],   dx     ; copy the value in register dx to the Variant to the first int16-slot
@@ -389,8 +389,10 @@ UInt64_Mul proc
     pushfd                  ; Save carry out here.
     
     ; 5. Multiply the two Hi dwords together,
-    mov   eax    , [esp+ 8] ; Get Hi dword of Multiplier
-    mul  dword ptr [esp+16] ; Multiply by Hi dword of Multiplicand
+    ;mov   eax    , [esp+ 8] ; Get Hi dword of Multiplier
+	mov   eax    , [esp+12]
+    ;mul  dword ptr [esp+16] ; Multiply by Hi dword of Multiplicand
+	mul  dword ptr [esp+20]
     popfd                   ; Retrieve carry from above
     adc   eax    ,  ecx     ; Add in partial product from above. 
     adc   edx    ,       0  ; Don't forget the carry!