Current File : //usr/local/go/src/runtime/sys_windows_arm.s
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "go_asm.h"
#include "go_tls.h"
#include "textflag.h"
#include "time_windows.h"
// Note: For system ABI, R0-R3 are args, R4-R11 are callee-save.
// void runtime·asmstdcall(void *c);
TEXT runtime·asmstdcall<ABIInternal>(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R5, R14], (R13) // push {r4, r5, lr}
MOVW R0, R4 // put libcall * in r4
MOVW R13, R5 // save stack pointer in r5
// SetLastError(0)
MOVW $0, R0
MRC 15, 0, R1, C13, C0, 2
MOVW R0, 0x34(R1)
MOVW 8(R4), R12 // libcall->args
// Do we have more than 4 arguments?
MOVW 4(R4), R0 // libcall->n
SUB.S $4, R0, R2
BLE loadregs
// Reserve stack space for remaining args
SUB R2<<2, R13
BIC $0x7, R13 // alignment for ABI
// R0: count of arguments
// R1:
// R2: loop counter, from 0 to (n-4)
// R3: scratch
// R4: pointer to libcall struct
// R12: libcall->args
MOVW $0, R2
stackargs:
ADD $4, R2, R3 // r3 = args[4 + i]
MOVW R3<<2(R12), R3
MOVW R3, R2<<2(R13) // stack[i] = r3
ADD $1, R2 // i++
SUB $4, R0, R3 // while (i < (n - 4))
CMP R3, R2
BLT stackargs
loadregs:
CMP $3, R0
MOVW.GT 12(R12), R3
CMP $2, R0
MOVW.GT 8(R12), R2
CMP $1, R0
MOVW.GT 4(R12), R1
CMP $0, R0
MOVW.GT 0(R12), R0
BIC $0x7, R13 // alignment for ABI
MOVW 0(R4), R12 // branch to libcall->fn
BL (R12)
MOVW R5, R13 // free stack space
MOVW R0, 12(R4) // save return value to libcall->r1
MOVW R1, 16(R4)
// GetLastError
MRC 15, 0, R1, C13, C0, 2
MOVW 0x34(R1), R0
MOVW R0, 20(R4) // store in libcall->err
MOVM.IA.W (R13), [R4, R5, R15]
TEXT runtime·badsignal2(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R14], (R13) // push {r4, lr}
MOVW R13, R4 // save original stack pointer
SUB $8, R13 // space for 2 variables
BIC $0x7, R13 // alignment for ABI
// stderr
MOVW runtime·_GetStdHandle(SB), R1
MOVW $-12, R0
BL (R1)
MOVW $runtime·badsignalmsg(SB), R1 // lpBuffer
MOVW $runtime·badsignallen(SB), R2 // lpNumberOfBytesToWrite
MOVW (R2), R2
ADD $0x4, R13, R3 // lpNumberOfBytesWritten
MOVW $0, R12 // lpOverlapped
MOVW R12, (R13)
MOVW runtime·_WriteFile(SB), R12
BL (R12)
// Does not return.
B runtime·abort(SB)
TEXT runtime·getlasterror(SB),NOSPLIT,$0
MRC 15, 0, R0, C13, C0, 2
MOVW 0x34(R0), R0
MOVW R0, ret+0(FP)
RET
// Called by Windows as a Vectored Exception Handler (VEH).
// First argument is pointer to struct containing
// exception record and context pointers.
// Handler function is stored in R1
// Return 0 for 'not handled', -1 for handled.
// int32_t sigtramp(
// PEXCEPTION_POINTERS ExceptionInfo,
// func *GoExceptionHandler);
TEXT sigtramp<>(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R0, R4-R11, R14], (R13) // push {r0, r4-r11, lr} (SP-=40)
SUB $(8+20), R13 // reserve space for g, sp, and
// parameters/retval to go call
MOVW R0, R6 // Save param0
MOVW R1, R7 // Save param1
BL runtime·load_g(SB)
CMP $0, g // is there a current g?
BL.EQ runtime·badsignal2(SB)
// save g and SP in case of stack switch
MOVW R13, 24(R13)
MOVW g, 20(R13)
// do we need to switch to the g0 stack?
MOVW g, R5 // R5 = g
MOVW g_m(R5), R2 // R2 = m
MOVW m_g0(R2), R4 // R4 = g0
CMP R5, R4 // if curg == g0
BEQ g0
// switch to g0 stack
MOVW R4, g // g = g0
MOVW (g_sched+gobuf_sp)(g), R3 // R3 = g->gobuf.sp
BL runtime·save_g(SB)
// make room for sighandler arguments
// and re-save old SP for restoring later.
// (note that the 24(R3) here must match the 24(R13) above.)
SUB $40, R3
MOVW R13, 24(R3) // save old stack pointer
MOVW R3, R13 // switch stack
g0:
MOVW 0(R6), R2 // R2 = ExceptionPointers->ExceptionRecord
MOVW 4(R6), R3 // R3 = ExceptionPointers->ContextRecord
MOVW $0, R4
MOVW R4, 0(R13) // No saved link register.
MOVW R2, 4(R13) // Move arg0 (ExceptionRecord) into position
MOVW R3, 8(R13) // Move arg1 (ContextRecord) into position
MOVW R5, 12(R13) // Move arg2 (original g) into position
BL (R7) // Call the goroutine
MOVW 16(R13), R4 // Fetch return value from stack
// Save system stack pointer for sigresume setup below.
// The exact value does not matter - nothing is read or written
// from this address. It just needs to be on the system stack.
MOVW R13, R12
// switch back to original stack and g
MOVW 24(R13), R13
MOVW 20(R13), g
BL runtime·save_g(SB)
done:
MOVW R4, R0 // move retval into position
ADD $(8 + 20), R13 // free locals
MOVM.IA.W (R13), [R3, R4-R11, R14] // pop {r3, r4-r11, lr}
// if return value is CONTINUE_SEARCH, do not set up control
// flow guard workaround
CMP $0, R0
BEQ return
// Check if we need to set up the control flow guard workaround.
// On Windows, the stack pointer in the context must lie within
// system stack limits when we resume from exception.
// Store the resume SP and PC on the g0 stack,
// and return to sigresume on the g0 stack. sigresume
// pops the saved PC and SP from the g0 stack, resuming execution
// at the desired location.
// If sigresume has already been set up by a previous exception
// handler, don't clobber the stored SP and PC on the stack.
MOVW 4(R3), R3 // PEXCEPTION_POINTERS->Context
MOVW context_pc(R3), R2 // load PC from context record
MOVW $sigresume<>(SB), R1
CMP R1, R2
B.EQ return // do not clobber saved SP/PC
// Save resume SP and PC into R0, R1.
MOVW context_spr(R3), R2
MOVW R2, context_r0(R3)
MOVW context_pc(R3), R2
MOVW R2, context_r1(R3)
// Set up context record to return to sigresume on g0 stack
MOVW R12, context_spr(R3)
MOVW $sigresume<>(SB), R2
MOVW R2, context_pc(R3)
return:
B (R14) // return
// Trampoline to resume execution from exception handler.
// This is part of the control flow guard workaround.
// It switches stacks and jumps to the continuation address.
// R0 and R1 are set above at the end of sigtramp<>
// in the context that starts executing at sigresume<>.
TEXT sigresume<>(SB),NOSPLIT|NOFRAME,$0
// Important: do not smash LR,
// which is set to a live value when handling
// a signal by pushing a call to sigpanic onto the stack.
MOVW R0, R13
B (R1)
TEXT runtime·exceptiontramp<ABIInternal>(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·exceptionhandler(SB), R1
B sigtramp<>(SB)
TEXT runtime·firstcontinuetramp<ABIInternal>(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·firstcontinuehandler(SB), R1
B sigtramp<>(SB)
TEXT runtime·lastcontinuetramp<ABIInternal>(SB),NOSPLIT|NOFRAME,$0
MOVW $runtime·lastcontinuehandler(SB), R1
B sigtramp<>(SB)
GLOBL runtime·cbctxts(SB), NOPTR, $4
TEXT runtime·callbackasm1<ABIInternal>(SB),NOSPLIT|NOFRAME,$0
// On entry, the trampoline in zcallback_windows_arm.s left
// the callback index in R12 (which is volatile in the C ABI).
// Push callback register arguments r0-r3. We do this first so
// they're contiguous with stack arguments.
MOVM.DB.W [R0-R3], (R13)
// Push C callee-save registers r4-r11 and lr.
MOVM.DB.W [R4-R11, R14], (R13)
SUB $(16 + callbackArgs__size), R13 // space for locals
// Create a struct callbackArgs on our stack.
MOVW R12, (16+callbackArgs_index)(R13) // callback index
MOVW $(16+callbackArgs__size+4*9)(R13), R0
MOVW R0, (16+callbackArgs_args)(R13) // address of args vector
MOVW $0, R0
MOVW R0, (16+callbackArgs_result)(R13) // result
// Prepare for entry to Go.
BL runtime·load_g(SB)
// Call cgocallback, which will call callbackWrap(frame).
MOVW $0, R0
MOVW R0, 12(R13) // context
MOVW $16(R13), R1 // R1 = &callbackArgs{...}
MOVW R1, 8(R13) // frame (address of callbackArgs)
MOVW $·callbackWrap(SB), R1
MOVW R1, 4(R13) // PC of function to call
BL runtime·cgocallback(SB)
// Get callback result.
MOVW (16+callbackArgs_result)(R13), R0
ADD $(16 + callbackArgs__size), R13 // free locals
MOVM.IA.W (R13), [R4-R11, R12] // pop {r4-r11, lr=>r12}
ADD $(4*4), R13 // skip r0-r3
B (R12) // return
// uint32 tstart_stdcall(M *newm);
TEXT runtime·tstart_stdcall<ABIInternal>(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4-R11, R14], (R13) // push {r4-r11, lr}
MOVW m_g0(R0), g
MOVW R0, g_m(g)
BL runtime·save_g(SB)
// Layout new m scheduler stack on os stack.
MOVW R13, R0
MOVW R0, g_stack+stack_hi(g)
SUB $(64*1024), R0
MOVW R0, (g_stack+stack_lo)(g)
MOVW R0, g_stackguard0(g)
MOVW R0, g_stackguard1(g)
BL runtime·emptyfunc(SB) // fault if stack check is wrong
BL runtime·mstart(SB)
// Exit the thread.
MOVW $0, R0
MOVM.IA.W (R13), [R4-R11, R15] // pop {r4-r11, pc}
// Runs on OS stack.
// duration (in -100ns units) is in dt+0(FP).
// g may be nil.
TEXT runtime·usleep2(SB),NOSPLIT|NOFRAME,$0-4
MOVW dt+0(FP), R3
MOVM.DB.W [R4, R14], (R13) // push {r4, lr}
MOVW R13, R4 // Save SP
SUB $8, R13 // R13 = R13 - 8
BIC $0x7, R13 // Align SP for ABI
MOVW $0, R1 // R1 = FALSE (alertable)
MOVW $-1, R0 // R0 = handle
MOVW R13, R2 // R2 = pTime
MOVW R3, 0(R2) // time_lo
MOVW R0, 4(R2) // time_hi
MOVW runtime·_NtWaitForSingleObject(SB), R3
BL (R3)
MOVW R4, R13 // Restore SP
MOVM.IA.W (R13), [R4, R15] // pop {R4, pc}
// Runs on OS stack.
// duration (in -100ns units) is in dt+0(FP).
// g is valid.
// TODO: neeeds to be implemented properly.
TEXT runtime·usleep2HighRes(SB),NOSPLIT|NOFRAME,$0-4
B runtime·abort(SB)
// Runs on OS stack.
TEXT runtime·switchtothread(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R14], (R13) // push {R4, lr}
MOVW R13, R4
BIC $0x7, R13 // alignment for ABI
MOVW runtime·_SwitchToThread(SB), R0
BL (R0)
MOVW R4, R13 // restore stack pointer
MOVM.IA.W (R13), [R4, R15] // pop {R4, pc}
TEXT ·publicationBarrier(SB),NOSPLIT|NOFRAME,$0-0
B runtime·armPublicationBarrier(SB)
// never called (this is a GOARM=7 platform)
TEXT runtime·read_tls_fallback(SB),NOSPLIT|NOFRAME,$0
MOVW $0xabcd, R0
MOVW R0, (R0)
RET
TEXT runtime·nanotime1(SB),NOSPLIT|NOFRAME,$0-8
MOVW $0, R0
MOVB runtime·useQPCTime(SB), R0
CMP $0, R0
BNE useQPC
MOVW $_INTERRUPT_TIME, R3
loop:
MOVW time_hi1(R3), R1
DMB MB_ISH
MOVW time_lo(R3), R0
DMB MB_ISH
MOVW time_hi2(R3), R2
CMP R1, R2
BNE loop
// wintime = R1:R0, multiply by 100
MOVW $100, R2
MULLU R0, R2, (R4, R3) // R4:R3 = R1:R0 * R2
MULA R1, R2, R4, R4
// wintime*100 = R4:R3
MOVW R3, ret_lo+0(FP)
MOVW R4, ret_hi+4(FP)
RET
useQPC:
B runtime·nanotimeQPC(SB) // tail call
// save_g saves the g register (R10) into thread local memory
// so that we can call externally compiled
// ARM code that will overwrite those registers.
// NOTE: runtime.gogo assumes that R1 is preserved by this function.
// runtime.mcall assumes this function only clobbers R0 and R11.
// Returns with g in R0.
// Save the value in the _TEB->TlsSlots array.
// Effectively implements TlsSetValue().
// tls_g stores the TLS slot allocated TlsAlloc().
TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0
MRC 15, 0, R0, C13, C0, 2
ADD $0xe10, R0
MOVW $runtime·tls_g(SB), R11
MOVW (R11), R11
MOVW g, R11<<2(R0)
MOVW g, R0 // preserve R0 across call to setg<>
RET
// load_g loads the g register from thread-local memory,
// for use after calling externally compiled
// ARM code that overwrote those registers.
// Get the value from the _TEB->TlsSlots array.
// Effectively implements TlsGetValue().
TEXT runtime·load_g(SB),NOSPLIT|NOFRAME,$0
MRC 15, 0, R0, C13, C0, 2
ADD $0xe10, R0
MOVW $runtime·tls_g(SB), g
MOVW (g), g
MOVW g<<2(R0), g
RET
// This is called from rt0_go, which runs on the system stack
// using the initial stack allocated by the OS.
// It calls back into standard C using the BL below.
// To do that, the stack pointer must be 8-byte-aligned.
TEXT runtime·_initcgo(SB),NOSPLIT|NOFRAME,$0
MOVM.DB.W [R4, R14], (R13) // push {r4, lr}
// Ensure stack is 8-byte aligned before calling C code
MOVW R13, R4
BIC $0x7, R13
// Allocate a TLS slot to hold g across calls to external code
MOVW $runtime·_TlsAlloc(SB), R0
MOVW (R0), R0
BL (R0)
// Assert that slot is less than 64 so we can use _TEB->TlsSlots
CMP $64, R0
MOVW $runtime·abort(SB), R1
BL.GE (R1)
// Save Slot into tls_g
MOVW $runtime·tls_g(SB), R1
MOVW R0, (R1)
MOVW R4, R13
MOVM.IA.W (R13), [R4, R15] // pop {r4, pc}
// Holds the TLS Slot, which was allocated by TlsAlloc()
GLOBL runtime·tls_g+0(SB), NOPTR, $4
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