petrbalvin
a0fa7e802c
Offsets beyond the split bands ride a per-function literal pool the way the toolchain lays one out: a PC-relative literal load into REGTMP, then the register-offset access (the pair family adds the base addition), the pooled words appended after the last instruction behind the UNDEF guard, deduplicated by value with the sign- and width-aware load selection. The same differential pass against the corpus exposed three wrong-code bugs and fixes them: the logical-immediate period marker rode the wrong position for every element below 64 bits, so the 32-bit forms encoded a different constant than written; the plain register operand of an ADD/SUB against SP took the shifted-register form where the toolchain uses the extended one with the identity extend, silently truncating through UXTB; and the AUTIA1716 and AUTIB1716 hint constants were the PACIA and PACIB encodings. An offset sweep across every band boundary now pins all three against the live oracle. Assisted-by: GLM 5.3 Flash
76 lines
1.7 KiB
ArmAsm
76 lines
1.7 KiB
ArmAsm
// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: BSD-3-Clause
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// Differential kernel for the arm64 synchronisation instructions: the
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// acquire/release loads and stores, the exclusive family and the LSE
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// atomics with acquire and release semantics, plus the register-pair
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// loads and stores. Every function is byte-compared against go tool asm.
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#include "textflag.h"
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// func acquireRelease()
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TEXT ·acquireRelease(SB), NOSPLIT, $0-0
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LDAR (R1), R2
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LDARB (R3), R4
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LDARH (R5), R6
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LDARW (R7), R8
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STLR R2, (R1)
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STLRB R4, (R3)
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STLRH R6, (R5)
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STLRW R8, (R7)
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RET
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// func exclusive()
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TEXT ·exclusive(SB), NOSPLIT, $0-0
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LDAXR (R1), R2
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LDAXRB (R3), R4
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LDAXRW (R5), R6
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STLXR R2, (R1), R8
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STLXRB R4, (R3), R8
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STLXRW R6, (R5), R8
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RET
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// func lseAcquireRelease()
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TEXT ·lseAcquireRelease(SB), NOSPLIT, $0-0
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CASALD R1, (R3), R2
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CASALW R4, (R6), R5
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LDADDALD R1, (R3), R2
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LDADDALW R4, (R6), R5
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LDCLRALB R1, (R3), R2
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LDCLRALW R4, (R6), R5
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LDCLRALD R1, (R3), R2
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LDORALB R1, (R3), R2
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LDORALW R4, (R6), R5
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LDORALD R1, (R3), R2
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SWPALB R1, (R3), R2
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SWPALW R4, (R6), R5
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SWPALD R1, (R3), R2
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RET
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// func lseBase()
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TEXT ·lseBase(SB), NOSPLIT, $0-0
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LDADDD R1, (R3), R2
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LDADDW R4, (R6), R5
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CASD R1, (R3), R2
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CASW R4, (R6), R5
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SWPD R1, (R3), R2
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SWPW R4, (R6), R5
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RET
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// func pairs()
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TEXT ·pairs(SB), NOSPLIT, $0-0
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LDP (R1), (R2, R3)
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LDP 8(R4), (R5, R6)
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LDP -16(R1), (R2, R3)
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LDPW 4(R4), (R5, R6)
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STP (R2, R3), 24(R7)
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STP (R2, R3),-8(R7)
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STPW (R1, R2), 4(R0)
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FLDPD (R8), (F1, F2)
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FLDPD 8(R8), (F3, F4)
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FSTPD (F3, F4),-8(R9)
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FLDPS 4(R8), (F1, F2)
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FLDPQ 16(R8), (F1, F2)
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FSTPQ (F1, F2), 48(R9)
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RET
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