70 lines
2.1 KiB
C
70 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* linux/arch/arm/kernel/opcodes.c
|
|
*
|
|
* A32 condition code lookup feature moved from nwfpe/fpopcode.c
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <asm/opcodes.h>
|
|
|
|
#define ARM_OPCODE_CONDITION_UNCOND 0xf
|
|
|
|
/*
|
|
* condition code lookup table
|
|
* index into the table is test code: EQ, NE, ... LT, GT, AL, NV
|
|
*
|
|
* bit position in short is condition code: NZCV
|
|
*/
|
|
static const unsigned short cc_map[16] = {
|
|
0xF0F0, /* EQ == Z set */
|
|
0x0F0F, /* NE */
|
|
0xCCCC, /* CS == C set */
|
|
0x3333, /* CC */
|
|
0xFF00, /* MI == N set */
|
|
0x00FF, /* PL */
|
|
0xAAAA, /* VS == V set */
|
|
0x5555, /* VC */
|
|
0x0C0C, /* HI == C set && Z clear */
|
|
0xF3F3, /* LS == C clear || Z set */
|
|
0xAA55, /* GE == (N==V) */
|
|
0x55AA, /* LT == (N!=V) */
|
|
0x0A05, /* GT == (!Z && (N==V)) */
|
|
0xF5FA, /* LE == (Z || (N!=V)) */
|
|
0xFFFF, /* AL always */
|
|
0 /* NV */
|
|
};
|
|
|
|
/*
|
|
* Returns:
|
|
* ARM_OPCODE_CONDTEST_FAIL - if condition fails
|
|
* ARM_OPCODE_CONDTEST_PASS - if condition passes (including AL)
|
|
* ARM_OPCODE_CONDTEST_UNCOND - if NV condition, or separate unconditional
|
|
* opcode space from v5 onwards
|
|
*
|
|
* Code that tests whether a conditional instruction would pass its condition
|
|
* check should check that return value == ARM_OPCODE_CONDTEST_PASS.
|
|
*
|
|
* Code that tests if a condition means that the instruction would be executed
|
|
* (regardless of conditional or unconditional) should instead check that the
|
|
* return value != ARM_OPCODE_CONDTEST_FAIL.
|
|
*/
|
|
asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr)
|
|
{
|
|
u32 cc_bits = opcode >> 28;
|
|
u32 psr_cond = psr >> 28;
|
|
unsigned int ret;
|
|
|
|
if (cc_bits != ARM_OPCODE_CONDITION_UNCOND) {
|
|
if ((cc_map[cc_bits] >> (psr_cond)) & 1)
|
|
ret = ARM_OPCODE_CONDTEST_PASS;
|
|
else
|
|
ret = ARM_OPCODE_CONDTEST_FAIL;
|
|
} else {
|
|
ret = ARM_OPCODE_CONDTEST_UNCOND;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(arm_check_condition);
|