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//
// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
//
//
// Implementation of _CONTEXT_CaptureContext for the ARM platform.
// This function is processor dependent. It is used by exception handling,
// and is always apply to the current thread.
//
#include "unixasmmacros.inc"
.syntax unified
.thumb
#define CONTEXT_ARM 0x00200000
#define CONTEXT_CONTROL 1 // Sp, Lr, Pc, Cpsr
#define CONTEXT_INTEGER 2 // R0-R12
#define CONTEXT_SEGMENTS 4 //
#define CONTEXT_FLOATING_POINT 8
#define CONTEXT_DEBUG_REGISTERS 16 //
#define CONTEXT_FULL (CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_FLOATING_POINT)
#define CONTEXT_ContextFlags 0
#define CONTEXT_R0 CONTEXT_ContextFlags+4
#define CONTEXT_R1 CONTEXT_R0+4
#define CONTEXT_R2 CONTEXT_R1+4
#define CONTEXT_R3 CONTEXT_R2+4
#define CONTEXT_R4 CONTEXT_R3+4
#define CONTEXT_R5 CONTEXT_R4+4
#define CONTEXT_R6 CONTEXT_R5+4
#define CONTEXT_R7 CONTEXT_R6+4
#define CONTEXT_R8 CONTEXT_R7+4
#define CONTEXT_R9 CONTEXT_R8+4
#define CONTEXT_R10 CONTEXT_R9+4
#define CONTEXT_R11 CONTEXT_R10+4
#define CONTEXT_R12 CONTEXT_R11+4
#define CONTEXT_Sp CONTEXT_R12+4
#define CONTEXT_Lr CONTEXT_Sp+4
#define CONTEXT_Pc CONTEXT_Lr+4
#define CONTEXT_Cpsr CONTEXT_Pc+4
#define CONTEXT_Fpscr CONTEXT_Cpsr+4
#define CONTEXT_Padding CONTEXT_Fpscr+4
#define CONTEXT_D0 CONTEXT_Padding+4
#define CONTEXT_D1 CONTEXT_D0+8
#define CONTEXT_D2 CONTEXT_D1+8
#define CONTEXT_D3 CONTEXT_D2+8
#define CONTEXT_D4 CONTEXT_D3+8
#define CONTEXT_D5 CONTEXT_D4+8
#define CONTEXT_D6 CONTEXT_D5+8
#define CONTEXT_D7 CONTEXT_D6+8
#define CONTEXT_D8 CONTEXT_D7+8
#define CONTEXT_D9 CONTEXT_D8+8
#define CONTEXT_D10 CONTEXT_D9+8
#define CONTEXT_D11 CONTEXT_D10+8
#define CONTEXT_D12 CONTEXT_D11+8
#define CONTEXT_D13 CONTEXT_D12+8
#define CONTEXT_D14 CONTEXT_D13+8
#define CONTEXT_D15 CONTEXT_D14+8
#define CONTEXT_D16 CONTEXT_D15+8
#define CONTEXT_D17 CONTEXT_D16+8
#define CONTEXT_D18 CONTEXT_D17+8
#define CONTEXT_D19 CONTEXT_D18+8
#define CONTEXT_D20 CONTEXT_D19+8
#define CONTEXT_D21 CONTEXT_D20+8
#define CONTEXT_D22 CONTEXT_D21+8
#define CONTEXT_D23 CONTEXT_D22+8
#define CONTEXT_D24 CONTEXT_D23+8
#define CONTEXT_D25 CONTEXT_D24+8
#define CONTEXT_D26 CONTEXT_D25+8
#define CONTEXT_D27 CONTEXT_D26+8
#define CONTEXT_D28 CONTEXT_D27+8
#define CONTEXT_D29 CONTEXT_D28+8
#define CONTEXT_D30 CONTEXT_D29+8
#define CONTEXT_D31 CONTEXT_D30+8
// Incoming:
// r0: Context*
//
LEAF_ENTRY CONTEXT_CaptureContext, _TEXT
// Ensure we save these registers
push {r4-r11}
// Save processor flags before calling any of the following 'test' instructions
// because they will modify state of some flags
push {r1}
mrs r1, apsr // Get APSR - equivalent to eflags
push {r1} // Save APSR
END_PROLOGUE
push {r2}
ldr r2, [r0, #(CONTEXT_ContextFlags)]
tst r2, #(CONTEXT_INTEGER)
pop {r2}
// Add 4 to stack so we point at R1, pop, then sub 8 to point at APSR
add sp, sp, #4
pop {r1}
sub sp, sp, #8
itttt ne
strne r0, [r0, #(CONTEXT_R0)]
addne r0, CONTEXT_R1
stmiane r0, {r1-r12}
subne r0, CONTEXT_R1
ldr r2, [r0, #(CONTEXT_ContextFlags)]
tst r2, #(CONTEXT_CONTROL)
ittt ne
addne sp, sp, #(10*4) // This needs to put the stack in the same state as it started
strne sp, [r0, #(CONTEXT_Sp)]
subne sp, sp, #(10*4)
itt ne
strne lr, [r0, #(CONTEXT_Lr)]
strne lr, [r0, #(CONTEXT_Pc)]
// Get the APSR pushed onto the stack at the start
pop {r1}
it ne
strne r1, [r0, #(CONTEXT_Cpsr)]
ldr r2, [r0, #(CONTEXT_ContextFlags)]
tst r2, #(CONTEXT_FLOATING_POINT)
itt ne
vmrsne r3, fpscr
strne r3, [r0, #(CONTEXT_Fpscr)]
itttt ne
addne r0, CONTEXT_D0
vstmiane r0!, {d0-d15}
vstmiane r0!, {d16-d31}
subne r0, CONTEXT_D31
// Make sure sp is restored
add sp, sp, #4
// Restore callee saved registers
pop {r4-r11}
bx lr
LEAF_END CONTEXT_CaptureContext, _TEXT
// Incoming:
// R0: Context*
//
LEAF_ENTRY RtlCaptureContext, _TEXT
push {r1}
mov r1, #0
orr r1, r1, #CONTEXT_ARM
orr r1, r1, #CONTEXT_INTEGER
orr r1, r1, #CONTEXT_CONTROL
orr r1, r1, #CONTEXT_FLOATING_POINT
str r1, [r0, #(CONTEXT_ContextFlags)]
pop {r1}
b C_FUNC(CONTEXT_CaptureContext)
LEAF_END RtlCaptureContext, _TEXT
// Incoming:
// r0: Context*
// r1: Exception*
//
LEAF_ENTRY RtlRestoreContext, _TEXT
END_PROLOGUE
ldr r2, [r0, #(CONTEXT_ContextFlags)]
tst r2, #(CONTEXT_FLOATING_POINT)
itttt ne
addne r0, CONTEXT_D0
vldmiane r0!, {d0-d15}
vldmiane r0, {d16-d31}
subne r0, CONTEXT_D16
itt ne
ldrne r3, [r0, #(CONTEXT_Fpscr)]
vmrsne r3, FPSCR
ldr r2, [r0, #(CONTEXT_ContextFlags)]
tst r2, #(CONTEXT_CONTROL)
it eq
beq LOCAL_LABEL(No_Restore_CONTEXT_CONTROL)
ldr r2, [r0, #(CONTEXT_ContextFlags)]
tst r2, #(CONTEXT_INTEGER)
it eq
beq LOCAL_LABEL(No_Restore_CONTEXT_INTEGER)
ldr R2, [r0, #(CONTEXT_Cpsr)]
msr APSR, r2
add r0, CONTEXT_R0
ldmia r0, {r0-r12, sp, lr, pc}
LOCAL_LABEL(No_Restore_CONTEXT_INTEGER):
ldr r2, [r0, #(CONTEXT_Cpsr)]
msr APSR, r2
add r0, CONTEXT_Sp
ldmia r0, {sp, lr, pc}
LOCAL_LABEL(No_Restore_CONTEXT_CONTROL):
ldr r2, [r0, #(CONTEXT_ContextFlags)]
tst r2, #(CONTEXT_INTEGER)
itt ne
addne r0, CONTEXT_R0
ldmiane r0, {r0-r12}
sub sp, sp, #4
bx lr
LEAF_END RtlRestoreContext, _TEXT
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