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Diffstat (limited to 'drivers/acpi/acpica/utmath.c')
| -rw-r--r-- | drivers/acpi/acpica/utmath.c | 494 |
1 files changed, 494 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/utmath.c b/drivers/acpi/acpica/utmath.c new file mode 100644 index 000000000..2c2c6bc1f --- /dev/null +++ b/drivers/acpi/acpica/utmath.c @@ -0,0 +1,494 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/******************************************************************************* + * + * Module Name: utmath - Integer math support routines + * + ******************************************************************************/ + +#include <acpi/acpi.h> +#include "accommon.h" + +#define _COMPONENT ACPI_UTILITIES +ACPI_MODULE_NAME("utmath") + +/* Structures used only for 64-bit divide */ +typedef struct uint64_struct { + u32 lo; + u32 hi; + +} uint64_struct; + +typedef union uint64_overlay { + u64 full; + struct uint64_struct part; + +} uint64_overlay; + +/* + * Optional support for 64-bit double-precision integer multiply and shift. + * This code is configurable and is implemented in order to support 32-bit + * kernel environments where a 64-bit double-precision math library is not + * available. + */ +#ifndef ACPI_USE_NATIVE_MATH64 + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_multiply + * + * PARAMETERS: multiplicand - 64-bit multiplicand + * multiplier - 32-bit multiplier + * out_product - Pointer to where the product is returned + * + * DESCRIPTION: Perform a short multiply. + * + ******************************************************************************/ + +acpi_status +acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product) +{ + union uint64_overlay multiplicand_ovl; + union uint64_overlay product; + u32 carry32; + + ACPI_FUNCTION_TRACE(ut_short_multiply); + + multiplicand_ovl.full = multiplicand; + + /* + * The Product is 64 bits, the carry is always 32 bits, + * and is generated by the second multiply. + */ + ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.hi, multiplier, + product.part.hi, carry32); + + ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.lo, multiplier, + product.part.lo, carry32); + + product.part.hi += carry32; + + /* Return only what was requested */ + + if (out_product) { + *out_product = product.full; + } + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_shift_left + * + * PARAMETERS: operand - 64-bit shift operand + * count - 32-bit shift count + * out_result - Pointer to where the result is returned + * + * DESCRIPTION: Perform a short left shift. + * + ******************************************************************************/ + +acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result) +{ + union uint64_overlay operand_ovl; + + ACPI_FUNCTION_TRACE(ut_short_shift_left); + + operand_ovl.full = operand; + + if ((count & 63) >= 32) { + operand_ovl.part.hi = operand_ovl.part.lo; + operand_ovl.part.lo = 0; + count = (count & 63) - 32; + } + ACPI_SHIFT_LEFT_64_BY_32(operand_ovl.part.hi, + operand_ovl.part.lo, count); + + /* Return only what was requested */ + + if (out_result) { + *out_result = operand_ovl.full; + } + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_shift_right + * + * PARAMETERS: operand - 64-bit shift operand + * count - 32-bit shift count + * out_result - Pointer to where the result is returned + * + * DESCRIPTION: Perform a short right shift. + * + ******************************************************************************/ + +acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result) +{ + union uint64_overlay operand_ovl; + + ACPI_FUNCTION_TRACE(ut_short_shift_right); + + operand_ovl.full = operand; + + if ((count & 63) >= 32) { + operand_ovl.part.lo = operand_ovl.part.hi; + operand_ovl.part.hi = 0; + count = (count & 63) - 32; + } + ACPI_SHIFT_RIGHT_64_BY_32(operand_ovl.part.hi, + operand_ovl.part.lo, count); + + /* Return only what was requested */ + + if (out_result) { + *out_result = operand_ovl.full; + } + + return_ACPI_STATUS(AE_OK); +} +#else + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_multiply + * + * PARAMETERS: See function headers above + * + * DESCRIPTION: Native version of the ut_short_multiply function. + * + ******************************************************************************/ + +acpi_status +acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product) +{ + + ACPI_FUNCTION_TRACE(ut_short_multiply); + + /* Return only what was requested */ + + if (out_product) { + *out_product = multiplicand * multiplier; + } + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_shift_left + * + * PARAMETERS: See function headers above + * + * DESCRIPTION: Native version of the ut_short_shift_left function. + * + ******************************************************************************/ + +acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result) +{ + + ACPI_FUNCTION_TRACE(ut_short_shift_left); + + /* Return only what was requested */ + + if (out_result) { + *out_result = operand << count; + } + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_shift_right + * + * PARAMETERS: See function headers above + * + * DESCRIPTION: Native version of the ut_short_shift_right function. + * + ******************************************************************************/ + +acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result) +{ + + ACPI_FUNCTION_TRACE(ut_short_shift_right); + + /* Return only what was requested */ + + if (out_result) { + *out_result = operand >> count; + } + + return_ACPI_STATUS(AE_OK); +} +#endif + +/* + * Optional support for 64-bit double-precision integer divide. This code + * is configurable and is implemented in order to support 32-bit kernel + * environments where a 64-bit double-precision math library is not available. + * + * Support for a more normal 64-bit divide/modulo (with check for a divide- + * by-zero) appears after this optional section of code. + */ +#ifndef ACPI_USE_NATIVE_DIVIDE + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_divide + * + * PARAMETERS: dividend - 64-bit dividend + * divisor - 32-bit divisor + * out_quotient - Pointer to where the quotient is returned + * out_remainder - Pointer to where the remainder is returned + * + * RETURN: Status (Checks for divide-by-zero) + * + * DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits) + * divide and modulo. The result is a 64-bit quotient and a + * 32-bit remainder. + * + ******************************************************************************/ + +acpi_status +acpi_ut_short_divide(u64 dividend, + u32 divisor, u64 *out_quotient, u32 *out_remainder) +{ + union uint64_overlay dividend_ovl; + union uint64_overlay quotient; + u32 remainder32; + + ACPI_FUNCTION_TRACE(ut_short_divide); + + /* Always check for a zero divisor */ + + if (divisor == 0) { + ACPI_ERROR((AE_INFO, "Divide by zero")); + return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO); + } + + dividend_ovl.full = dividend; + + /* + * 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_ovl.part.hi, divisor, + quotient.part.hi, remainder32); + + ACPI_DIV_64_BY_32(remainder32, dividend_ovl.part.lo, divisor, + quotient.part.lo, remainder32); + + /* Return only what was requested */ + + if (out_quotient) { + *out_quotient = quotient.full; + } + if (out_remainder) { + *out_remainder = remainder32; + } + + return_ACPI_STATUS(AE_OK); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ut_divide + * + * PARAMETERS: in_dividend - Dividend + * in_divisor - Divisor + * out_quotient - Pointer to where the quotient is returned + * out_remainder - Pointer to where the remainder is returned + * + * RETURN: Status (Checks for divide-by-zero) + * + * DESCRIPTION: Perform a divide and modulo. + * + ******************************************************************************/ + +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); + + /* 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 = (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--; + } + } + } + + /* Return only what was requested */ + + if (out_quotient) { + *out_quotient = quotient.full; + } + if (out_remainder) { + *out_remainder = remainder.full; + } + + return_ACPI_STATUS(AE_OK); +} + +#else + +/******************************************************************************* + * + * FUNCTION: acpi_ut_short_divide, acpi_ut_divide + * + * PARAMETERS: See function headers above + * + * DESCRIPTION: Native versions of the ut_divide functions. Use these if either + * 1) The target is a 64-bit platform and therefore 64-bit + * integer math is supported directly by the machine. + * 2) The target is a 32-bit or 16-bit platform, and the + * double-precision integer math library is available to + * perform the divide. + * + ******************************************************************************/ + +acpi_status +acpi_ut_short_divide(u64 in_dividend, + u32 divisor, u64 *out_quotient, u32 *out_remainder) +{ + + ACPI_FUNCTION_TRACE(ut_short_divide); + + /* Always check for a zero divisor */ + + if (divisor == 0) { + ACPI_ERROR((AE_INFO, "Divide by zero")); + return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO); + } + + /* Return only what was requested */ + + if (out_quotient) { + *out_quotient = in_dividend / divisor; + } + if (out_remainder) { + *out_remainder = (u32) (in_dividend % divisor); + } + + return_ACPI_STATUS(AE_OK); +} + +acpi_status +acpi_ut_divide(u64 in_dividend, + u64 in_divisor, u64 *out_quotient, u64 *out_remainder) +{ + 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); + } + + /* Return only what was requested */ + + if (out_quotient) { + *out_quotient = in_dividend / in_divisor; + } + if (out_remainder) { + *out_remainder = in_dividend % in_divisor; + } + + return_ACPI_STATUS(AE_OK); +} + +#endif |