gmp_lib.mpn_submul_1 Method

GMP Native Interface for .NET

previous page next page
gmp_libmpn_submul_1 Method
Multiply {s1p, n} and s2limb, and subtract the n least significant limbs of the product from {rp, n} and write the result to rp.

Namespace:  Math.Gmp.Native
Assembly:  Math.Gmp.Native (in Math.Gmp.Native.dll) Version: 1.0.0.0 (1.0.0.0)
Syntax
Copy
public static mp_limb_t mpn_submul_1(
	mp_ptr rp,
	mp_ptr s1p,
	mp_size_t n,
	mp_limb_t s2limb
)
Public Shared Function mpn_submul_1 ( 
	rp As mp_ptr,
	s1p As mp_ptr,
	n As mp_size_t,
	s2limb As mp_limb_t
) As mp_limb_t
public:
static mp_limb_t mpn_submul_1(
	mp_ptr^ rp, 
	mp_ptr^ s1p, 
	mp_size_t n, 
	mp_limb_t s2limb
)
static member mpn_submul_1 : 
        rp : mp_ptr * 
        s1p : mp_ptr * 
        n : mp_size_t * 
        s2limb : mp_limb_t -> mp_limb_t

Parameters

rp
Type: Math.Gmp.Nativemp_ptr
The result integer.
s1p
Type: Math.Gmp.Nativemp_ptr
The first operand integer.
n
Type: Math.Gmp.Nativemp_size_t
The number of limbs of s1p
s2limb
Type: Math.Gmp.Nativemp_limb_t
The second operand integer.

Return Value

Type: mp_limb_t
Return the most significant limb of the product, plus borrow-out from the subtraction.
Remarks

{s1p, n} and {rp, n} are allowed to overlap provided rp ≤ s1p.

This is a low-level function that is a building block for general multiplication and division as well as other operations in GMP. It is written in assembly for most CPUs.

Examples
Copy
// Create multi-precision operands, and expected result.
mp_ptr s1p = new mp_ptr(new uint[] { 0xffffffff, 0xffffffff });
mp_ptr rp = new mp_ptr(new uint[] { 0x00000002, 0x00000000 });
mp_ptr result = new mp_ptr(new uint[] { 0x00000004, 0x00000000 });

// Set rp -= s1 * 2.
mp_limb_t borrow = gmp_lib.mpn_submul_1(rp, s1p, s1p.Size, 2);

// Assert result of operation.
Assert.IsTrue(borrow == 0x02);
Assert.IsTrue(rp.SequenceEqual(result));

// Release unmanaged memory.
gmp_lib.free(rp, s1p, result);
' Create multi-precision operands, and expected result.
Dim s1p As New mp_ptr(New UInteger() { &HffffffffUI, &HffffffffUI})
Dim rp As New mp_ptr(New UInteger() { &H2, &H0})
Dim result As New mp_ptr(New UInteger() { &H4, &H0})

' Set rp -= s1 * 2.
Dim borrow As mp_limb_t = gmp_lib.mpn_submul_1(rp, s1p, s1p.Size, 2)

' Assert result of operation.
Assert.IsTrue(borrow = &H2)
Assert.IsTrue(rp.SequenceEqual(result))

' Release unmanaged memory.
gmp_lib.free(rp, s1p, result)

No code example is currently available or this language may not be supported.

No code example is currently available or this language may not be supported.

See Also
previous page start next page