diff options
Diffstat (limited to 'lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp')
| -rw-r--r-- | lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp | 88 |
1 files changed, 57 insertions, 31 deletions
diff --git a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp index 95506775af..ac6ce642df 100644 --- a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp +++ b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp @@ -394,39 +394,65 @@ static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value, return swapped; } case ARM::fixup_arm_thumb_bl: { - // The value doesn't encode the low bit (always zero) and is offset by - // four. The value is encoded into disjoint bit positions in the destination - // opcode. x = unchanged, I = immediate value bit, S = sign extension bit - // - // BL: xxxxxSIIIIIIIIII xxxxxIIIIIIIIIII - // - // Note that the halfwords are stored high first, low second; so we need - // to transpose the fixup value here to map properly. - unsigned isNeg = (int64_t(Value - 4) < 0) ? 1 : 0; - uint32_t Binary = 0; - Value = 0x3fffff & ((Value - 4) >> 1); - Binary = (Value & 0x7ff) << 16; // Low imm11 value. - Binary |= (Value & 0x1ffc00) >> 11; // High imm10 value. - Binary |= isNeg << 10; // Sign bit. - return Binary; + // The value doesn't encode the low bit (always zero) and is offset by + // four. The 32-bit immediate value is encoded as + // imm32 = SignExtend(S:I1:I2:imm10:imm11:0) + // where I1 = NOT(J1 ^ S) and I2 = NOT(J2 ^ S). + // The value is encoded into disjoint bit positions in the destination + // opcode. x = unchanged, I = immediate value bit, S = sign extension bit, + // J = either J1 or J2 bit + // + // BL: xxxxxSIIIIIIIIII xxJxJIIIIIIIIIII + // + // Note that the halfwords are stored high first, low second; so we need + // to transpose the fixup value here to map properly. + uint32_t offset = (Value - 4) >> 1; + uint32_t signBit = (offset & 0x800000) >> 23; + uint32_t I1Bit = (offset & 0x400000) >> 22; + uint32_t J1Bit = (I1Bit ^ 0x1) ^ signBit; + uint32_t I2Bit = (offset & 0x200000) >> 21; + uint32_t J2Bit = (I2Bit ^ 0x1) ^ signBit; + uint32_t imm10Bits = (offset & 0x1FF800) >> 11; + uint32_t imm11Bits = (offset & 0x000007FF); + + uint32_t Binary = 0; + uint32_t firstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10Bits); + uint32_t secondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) | + (uint16_t)imm11Bits); + Binary |= secondHalf << 16; + Binary |= firstHalf; + return Binary; + } case ARM::fixup_arm_thumb_blx: { - // The value doesn't encode the low two bits (always zero) and is offset by - // four (see fixup_arm_thumb_cp). The value is encoded into disjoint bit - // positions in the destination opcode. x = unchanged, I = immediate value - // bit, S = sign extension bit, 0 = zero. - // - // BLX: xxxxxSIIIIIIIIII xxxxxIIIIIIIIII0 - // - // Note that the halfwords are stored high first, low second; so we need - // to transpose the fixup value here to map properly. - unsigned isNeg = (int64_t(Value-4) < 0) ? 1 : 0; - uint32_t Binary = 0; - Value = 0xfffff & ((Value - 2) >> 2); - Binary = (Value & 0x3ff) << 17; // Low imm10L value. - Binary |= (Value & 0xffc00) >> 10; // High imm10H value. - Binary |= isNeg << 10; // Sign bit. - return Binary; + // The value doesn't encode the low two bits (always zero) and is offset by + // four (see fixup_arm_thumb_cp). The 32-bit immediate value is encoded as + // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:00) + // where I1 = NOT(J1 ^ S) and I2 = NOT(J2 ^ S). + // The value is encoded into disjoint bit positions in the destination + // opcode. x = unchanged, I = immediate value bit, S = sign extension bit, + // J = either J1 or J2 bit, 0 = zero. + // + // BLX: xxxxxSIIIIIIIIII xxJxJIIIIIIIIII0 + // + // Note that the halfwords are stored high first, low second; so we need + // to transpose the fixup value here to map properly. + uint32_t offset = (Value - 2) >> 2; + uint32_t signBit = (offset & 0x400000) >> 22; + uint32_t I1Bit = (offset & 0x200000) >> 21; + uint32_t J1Bit = (I1Bit ^ 0x1) ^ signBit; + uint32_t I2Bit = (offset & 0x100000) >> 20; + uint32_t J2Bit = (I2Bit ^ 0x1) ^ signBit; + uint32_t imm10HBits = (offset & 0xFFC00) >> 10; + uint32_t imm10LBits = (offset & 0x3FF); + + uint32_t Binary = 0; + uint32_t firstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10HBits); + uint32_t secondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) | + ((uint16_t)imm10LBits) << 1); + Binary |= secondHalf << 16; + Binary |= firstHalf; + return Binary; } case ARM::fixup_arm_thumb_cp: // Offset by 4, and don't encode the low two bits. Two bytes of that |