github.com/jwijenbergh/purego@v0.0.0-20240126093400-70ff3a61df13/sys_unix_arm64.s (about) 1 // SPDX-License-Identifier: Apache-2.0 2 // SPDX-FileCopyrightText: 2023 The Ebitengine Authors 3 4 //go:build darwin || freebsd || linux 5 6 #include "textflag.h" 7 #include "go_asm.h" 8 #include "funcdata.h" 9 #include "abi_arm64.h" 10 11 TEXT callbackasm1(SB), NOSPLIT|NOFRAME, $0 12 NO_LOCAL_POINTERS 13 14 // On entry, the trampoline in zcallback_darwin_arm64.s left 15 // the callback index in R12 (which is volatile in the C ABI). 16 17 // Save callback register arguments R0-R7 and F0-F7. 18 // We do this at the top of the frame so they're contiguous with stack arguments. 19 SUB $(16*8), RSP, R14 20 FSTPD (F0, F1), (0*8)(R14) 21 FSTPD (F2, F3), (2*8)(R14) 22 FSTPD (F4, F5), (4*8)(R14) 23 FSTPD (F6, F7), (6*8)(R14) 24 STP (R0, R1), (8*8)(R14) 25 STP (R2, R3), (10*8)(R14) 26 STP (R4, R5), (12*8)(R14) 27 STP (R6, R7), (14*8)(R14) 28 29 // Adjust SP by frame size. 30 SUB $(26*8), RSP 31 32 // It is important to save R27 because the go assembler 33 // uses it for move instructions for a variable. 34 // This line: 35 // MOVD ·callbackWrap_call(SB), R0 36 // Creates the instructions: 37 // ADRP 14335(PC), R27 38 // MOVD 388(27), R0 39 // R27 is a callee saved register so we are responsible 40 // for ensuring its value doesn't change. So save it and 41 // restore it at the end of this function. 42 // R30 is the link register. crosscall2 doesn't save it 43 // so it's saved here. 44 STP (R27, R30), 0(RSP) 45 46 // Create a struct callbackArgs on our stack. 47 MOVD $(callbackArgs__size)(RSP), R13 48 MOVD R12, callbackArgs_index(R13) // callback index 49 MOVD R14, callbackArgs_args(R13) // address of args vector 50 MOVD ZR, callbackArgs_result(R13) // result 51 52 // Move parameters into registers 53 // Get the ABIInternal function pointer 54 // without <ABIInternal> by using a closure. 55 MOVD ·callbackWrap_call(SB), R0 56 MOVD (R0), R0 // fn unsafe.Pointer 57 MOVD R13, R1 // frame (&callbackArgs{...}) 58 MOVD $0, R3 // ctxt uintptr 59 60 BL crosscall2(SB) 61 62 // Get callback result. 63 MOVD $(callbackArgs__size)(RSP), R13 64 MOVD callbackArgs_result(R13), R0 65 66 // Restore LR and R27 67 LDP 0(RSP), (R27, R30) 68 ADD $(26*8), RSP 69 70 RET