ACPI_STATUS
AcpiUtDivide (
UINT64 InDividend,
UINT64 InDivisor,
UINT64 *OutQuotient,
UINT64 *OutRemainder)
{
UINT64_OVERLAY Dividend;
UINT64_OVERLAY Divisor;
UINT64_OVERLAY Quotient;
UINT64_OVERLAY Remainder;
UINT64_OVERLAY NormalizedDividend;
UINT64_OVERLAY NormalizedDivisor;
UINT32 Partial1;
UINT64_OVERLAY Partial2;
UINT64_OVERLAY Partial3;
ACPI_FUNCTION_TRACE (UtDivide);
/* Always check for a zero divisor */
if (InDivisor == 0)
{
ACPI_ERROR ((AE_INFO, "Divide by zero"));
return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
}
Divisor.Full = InDivisor;
Dividend.Full = InDividend;
if (Divisor.Part.Hi == 0)
{
/*
* 1) Simplest case is where the divisor is 32 bits, we can
* just do two divides
*/
Remainder.Part.Hi = 0;
/*
* The quotient is 64 bits, the remainder is always 32 bits,
* and is generated by the second divide.
*/
ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo,
Quotient.Part.Hi, Partial1);
ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo,
Quotient.Part.Lo, Remainder.Part.Lo);
}
else
{
/*
* 2) The general case where the divisor is a full 64 bits
* is more difficult
*/
Quotient.Part.Hi = 0;
NormalizedDividend = Dividend;
NormalizedDivisor = Divisor;
/* Normalize the operands (shift until the divisor is < 32 bits) */
do
{
ACPI_SHIFT_RIGHT_64 (NormalizedDivisor.Part.Hi,
NormalizedDivisor.Part.Lo);
ACPI_SHIFT_RIGHT_64 (NormalizedDividend.Part.Hi,
NormalizedDividend.Part.Lo);
} while (NormalizedDivisor.Part.Hi != 0);
/* Partial divide */
ACPI_DIV_64_BY_32 (NormalizedDividend.Part.Hi,
NormalizedDividend.Part.Lo,
NormalizedDivisor.Part.Lo,
Quotient.Part.Lo, Partial1);
/*
* The quotient is always 32 bits, and simply requires adjustment.
* The 64-bit remainder must be generated.
*/
Partial1 = Quotient.Part.Lo * Divisor.Part.Hi;
Partial2.Full = (UINT64) Quotient.Part.Lo * Divisor.Part.Lo;
Partial3.Full = (UINT64) Partial2.Part.Hi + Partial1;
Remainder.Part.Hi = Partial3.Part.Lo;
Remainder.Part.Lo = Partial2.Part.Lo;
if (Partial3.Part.Hi == 0)
{
if (Partial3.Part.Lo >= Dividend.Part.Hi)
{
if (Partial3.Part.Lo == Dividend.Part.Hi)
{
if (Partial2.Part.Lo > Dividend.Part.Lo)
{
Quotient.Part.Lo--;
Remainder.Full -= Divisor.Full;
}
}
else
{
Quotient.Part.Lo--;
Remainder.Full -= Divisor.Full;
}
}
Remainder.Full = Remainder.Full - Dividend.Full;
Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi);
Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo);
if (Remainder.Part.Lo)
{
Remainder.Part.Hi--;
}
}
}
/* Return only what was requested */
if (OutQuotient)
{
*OutQuotient = Quotient.Full;
}
if (OutRemainder)
{
*OutRemainder = Remainder.Full;
}
return_ACPI_STATUS (AE_OK);
}
acpi_status
acpi_ut_divide(acpi_integer in_dividend,
acpi_integer in_divisor,
acpi_integer * out_quotient, acpi_integer * out_remainder)
{
union uint64_overlay dividend;
union uint64_overlay divisor;
union uint64_overlay quotient;
union uint64_overlay remainder;
union uint64_overlay normalized_dividend;
union uint64_overlay normalized_divisor;
u32 partial1;
union uint64_overlay partial2;
union uint64_overlay partial3;
ACPI_FUNCTION_TRACE(ut_divide);
/* Always check for a zero divisor */
if (in_divisor == 0) {
ACPI_ERROR((AE_INFO, "Divide by zero"));
return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
}
divisor.full = in_divisor;
dividend.full = in_dividend;
if (divisor.part.hi == 0) {
/*
* 1) Simplest case is where the divisor is 32 bits, we can
* just do two divides
*/
remainder.part.hi = 0;
/*
* The quotient is 64 bits, the remainder is always 32 bits,
* and is generated by the second divide.
*/
ACPI_DIV_64_BY_32(0, dividend.part.hi, divisor.part.lo,
quotient.part.hi, partial1);
ACPI_DIV_64_BY_32(partial1, dividend.part.lo, divisor.part.lo,
quotient.part.lo, remainder.part.lo);
}
else {
/*
* 2) The general case where the divisor is a full 64 bits
* is more difficult
*/
quotient.part.hi = 0;
normalized_dividend = dividend;
normalized_divisor = divisor;
/* Normalize the operands (shift until the divisor is < 32 bits) */
do {
ACPI_SHIFT_RIGHT_64(normalized_divisor.part.hi,
normalized_divisor.part.lo);
ACPI_SHIFT_RIGHT_64(normalized_dividend.part.hi,
normalized_dividend.part.lo);
} while (normalized_divisor.part.hi != 0);
/* Partial divide */
ACPI_DIV_64_BY_32(normalized_dividend.part.hi,
normalized_dividend.part.lo,
normalized_divisor.part.lo,
quotient.part.lo, partial1);
/*
* The quotient is always 32 bits, and simply requires adjustment.
* The 64-bit remainder must be generated.
*/
partial1 = quotient.part.lo * divisor.part.hi;
partial2.full =
(acpi_integer) quotient.part.lo * divisor.part.lo;
partial3.full = (acpi_integer) partial2.part.hi + partial1;
remainder.part.hi = partial3.part.lo;
remainder.part.lo = partial2.part.lo;
if (partial3.part.hi == 0) {
if (partial3.part.lo >= dividend.part.hi) {
if (partial3.part.lo == dividend.part.hi) {
if (partial2.part.lo > dividend.part.lo) {
quotient.part.lo--;
remainder.full -= divisor.full;
}
} else {
quotient.part.lo--;
remainder.full -= divisor.full;
}
}
remainder.full = remainder.full - dividend.full;
remainder.part.hi = (u32) - ((s32) remainder.part.hi);
remainder.part.lo = (u32) - ((s32) remainder.part.lo);
if (remainder.part.lo) {
remainder.part.hi--;
}
}
}
/* Return only what was requested */
if (out_quotient) {
*out_quotient = quotient.full;
}
if (out_remainder) {
*out_remainder = remainder.full;
}
return_ACPI_STATUS(AE_OK);
}
acpi_status
acpi_ut_divide(u64 in_dividend,
u64 in_divisor, u64 *out_quotient, u64 *out_remainder)
{
union uint64_overlay dividend;
union uint64_overlay divisor;
union uint64_overlay quotient;
union uint64_overlay remainder;
union uint64_overlay normalized_dividend;
union uint64_overlay normalized_divisor;
u32 partial1;
union uint64_overlay partial2;
union uint64_overlay partial3;
ACPI_FUNCTION_TRACE(ut_divide);
if (in_divisor == 0) {
ACPI_ERROR((AE_INFO, "Divide by zero"));
return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
}
divisor.full = in_divisor;
dividend.full = in_dividend;
if (divisor.part.hi == 0) {
remainder.part.hi = 0;
ACPI_DIV_64_BY_32(0, dividend.part.hi, divisor.part.lo,
quotient.part.hi, partial1);
ACPI_DIV_64_BY_32(partial1, dividend.part.lo, divisor.part.lo,
quotient.part.lo, remainder.part.lo);
}
else {
quotient.part.hi = 0;
normalized_dividend = dividend;
normalized_divisor = divisor;
do {
ACPI_SHIFT_RIGHT_64(normalized_divisor.part.hi,
normalized_divisor.part.lo);
ACPI_SHIFT_RIGHT_64(normalized_dividend.part.hi,
normalized_dividend.part.lo);
} while (normalized_divisor.part.hi != 0);
ACPI_DIV_64_BY_32(normalized_dividend.part.hi,
normalized_dividend.part.lo,
normalized_divisor.part.lo,
quotient.part.lo, partial1);
partial1 = quotient.part.lo * divisor.part.hi;
partial2.full = (u64) quotient.part.lo * divisor.part.lo;
partial3.full = (u64) partial2.part.hi + partial1;
remainder.part.hi = partial3.part.lo;
remainder.part.lo = partial2.part.lo;
if (partial3.part.hi == 0) {
if (partial3.part.lo >= dividend.part.hi) {
if (partial3.part.lo == dividend.part.hi) {
if (partial2.part.lo > dividend.part.lo) {
quotient.part.lo--;
remainder.full -= divisor.full;
}
} else {
quotient.part.lo--;
remainder.full -= divisor.full;
}
}
remainder.full = remainder.full - dividend.full;
remainder.part.hi = (u32) - ((s32) remainder.part.hi);
remainder.part.lo = (u32) - ((s32) remainder.part.lo);
if (remainder.part.lo) {
remainder.part.hi--;
}
}
}
if (out_quotient) {
*out_quotient = quotient.full;
}
if (out_remainder) {
*out_remainder = remainder.full;
}
return_ACPI_STATUS(AE_OK);
}