// Copyright 2019 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#if defined(__aarch64__)

#include "OSFiber_asm_aarch64.h"

// void yarn_fiber_swap(yarn_fiber_context* from, const yarn_fiber_context* to)
// x0: from
// x1: to
.text
.global YARN_ASM_SYMBOL(yarn_fiber_swap)
.align 4
YARN_ASM_SYMBOL(yarn_fiber_swap):

    // Save context 'from'
    // TODO: pairs of str can be combined with stp.

    // Store special purpose registers
    str x16, [x0, #YARN_REG_r16]
    str x17, [x0, #YARN_REG_r17]
    str x18, [x0, #YARN_REG_r18]

    // Store callee-preserved registers
    str x19, [x0, #YARN_REG_r19]
    str x20, [x0, #YARN_REG_r20]
    str x21, [x0, #YARN_REG_r21]
    str x22, [x0, #YARN_REG_r22]
    str x23, [x0, #YARN_REG_r23]
    str x24, [x0, #YARN_REG_r24]
    str x25, [x0, #YARN_REG_r25]
    str x26, [x0, #YARN_REG_r26]
    str x27, [x0, #YARN_REG_r27]
    str x28, [x0, #YARN_REG_r28]

    str d8,  [x0, #YARN_REG_v8]
    str d9,  [x0, #YARN_REG_v9]
    str d10, [x0, #YARN_REG_v10]
    str d11, [x0, #YARN_REG_v11]
    str d12, [x0, #YARN_REG_v12]
    str d13, [x0, #YARN_REG_v13]
    str d14, [x0, #YARN_REG_v14]
    str d15, [x0, #YARN_REG_v15]

    // Store sp and lr
    mov x2, sp
    str x2,  [x0, #YARN_REG_SP]
    str x30, [x0, #YARN_REG_LR]

    // Load context 'to'
    mov x7, x1

    // Load special purpose registers
    ldr x16, [x7, #YARN_REG_r16]
    ldr x17, [x7, #YARN_REG_r17]
    ldr x18, [x7, #YARN_REG_r18]

    // Load callee-preserved registers
    ldr x19, [x7, #YARN_REG_r19]
    ldr x20, [x7, #YARN_REG_r20]
    ldr x21, [x7, #YARN_REG_r21]
    ldr x22, [x7, #YARN_REG_r22]
    ldr x23, [x7, #YARN_REG_r23]
    ldr x24, [x7, #YARN_REG_r24]
    ldr x25, [x7, #YARN_REG_r25]
    ldr x26, [x7, #YARN_REG_r26]
    ldr x27, [x7, #YARN_REG_r27]
    ldr x28, [x7, #YARN_REG_r28]

    ldr d8,  [x7, #YARN_REG_v8]
    ldr d9,  [x7, #YARN_REG_v9]
    ldr d10, [x7, #YARN_REG_v10]
    ldr d11, [x7, #YARN_REG_v11]
    ldr d12, [x7, #YARN_REG_v12]
    ldr d13, [x7, #YARN_REG_v13]
    ldr d14, [x7, #YARN_REG_v14]
    ldr d15, [x7, #YARN_REG_v15]

    // Load parameter registers
    ldr x0, [x7, #YARN_REG_r0]
    ldr x1, [x7, #YARN_REG_r1]

    // Load sp and lr
    ldr x30, [x7, #YARN_REG_LR]
    ldr x2,  [x7, #YARN_REG_SP]
    mov sp, x2

    ret

#endif // defined(__aarch64__)