// Copyright 2020 Google LLC
//
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree.

#include <xnnpack/assembly.h>

# void xnn_f16_gemm${"inc" if INC else ""}_minmax_ukernel_6x8__aarch64_neonfp16arith_ld64(
#     size_t mr,                x0
#     size_t nc,                x1
#     size_t kc,                x2 / x0
#     const void*restrict a,    x3
#     size_t a_stride,          x4
#     const void*restrict w,    x5
#     void*restrict c,          x6
#     size_t cm_stride,         x7
#     size_t cn_stride,         [sp] -> (x8)
$if INC:
  #     const float*restrict acc,  [sp + 8] -> x15
  #     const union xnn_f16_minmax_params params[restrict XNN_MIN_ELEMENTS(1)])  [sp + 16] -> (x8)
$else:
  #     const union xnn_f16_minmax_params params[restrict XNN_MIN_ELEMENTS(1)])  [sp + 8] -> (x8)

# d8-d15, x19-x30 need to be preserved if used. x18 is reserved by the OS.

# A pointers
#  x3 a0
#  x9 a1
# x10 a2
# x11 a3
# x12 a4
#  x4 a5

# C pointers
#  x6 c0
# x16 c1
# x17 c2
# x14 c3
# x13 c4
#  x7 c5

# Vector register usage
# A0   v0
# A1   v1
# A2   v2
# A3   v3
# A4   v4
# A5   v5
# B   v16 v17 v18 v19
# C   v20
# C   v22
# C   v24
# C   v26
# C   v28
# C   v30
# Clamp v6, (v4), (v5)
# unused A   v8 v9 v10 v11
# unused B   v12 v13 v14 v15


BEGIN_FUNCTION xnn_f16_gemm${"inc" if INC else ""}_minmax_ukernel_6x8__aarch64_neonfp16arith_ld64

        $if INC:
          # Load acc, params pointer
          LDP     x15, x8, [sp, 8]
        $else:
          # Load params pointer
          LDR     x8, [sp, 8]

        # Clamp A and C pointers
        CMP     x0, 2                   // if mr < 2
        ADD     x9, x3, x4              // a1 = a0 + a_stride
        ADD     x16, x6, x7             // c1 = c0 + cm_stride
        CSEL    x9, x3, x9, LO          //   a1 = a0
        CSEL    x16, x6, x16, LO        //   c1 = c0

        # Load params
        LDR     s6, [x8]

        ADD     x10, x9, x4             // a2 = a1 + a_stride
        ADD     x17, x16, x7            // c2 = c1 + cm_stride
                                        // if mr <= 2
        CSEL    x10, x9, x10, LS        //   a2 = a1
        CSEL    x17, x16, x17, LS       //   c2 = c1

        CMP     x0, 4                   // if mr < 4
        ADD     x11, x10, x4            // a3 = a2 + a_stride
        ADD     x14, x17, x7            // c3 = c2 + cm_stride
        CSEL    x11, x10, x11, LO       //   a3 = a2
        CSEL    x14, x17, x14, LO       //   c3 = c2

        ADD     x12, x11, x4            // a4 = a3 + a_stride
        ADD     x13, x14, x7            // c4 = c3 + cm_stride
                                        // if mr <= 4
        CSEL    x12, x11, x12, LS       //   a4 = a3
        CSEL    x13, x14, x13, LS       //   c4 = c3

        CMP     x0, 6                   // if mr < 6
        ADD     x4, x12, x4             // a5 = a4 + a_stride
        ADD     x7, x13, x7             // c5 = c4 + cm_stride
        CSEL    x4, x12, x4, LO         //   a5 = a4
        CSEL    x7, x13, x7, LO         //   c5 = c4

        LDR     x8, [sp]                // load cn_stride

0:
        $if INC:
          # Load initial accumulators
          LDP     q20, q22, [x15], 32
          LDP     q24, q26, [x15], 32
          LDP     q28, q30, [x15], 32
        $else:
          # Load initial bias from w into accumulators
          LDR     q20, [x5], 16
          MOV     v22.16b, v20.16b
          MOV     v24.16b, v20.16b
          MOV     v26.16b, v20.16b
          MOV     v28.16b, v20.16b
          MOV     v30.16b, v20.16b

         # Is there at least 4 halffloats (8 bytes)?
        SUBS    x0, x2, 8               // k = kc - 8
        B.LO    3f

        # Main loop - 4 halffloats of A (8 bytes)
        # 24 FMA + 6 ld64 A + 4 LDR B
1:
        LDR     d0,  [x3], 8
        LDR     q16, [x5], 16
        LDR     q17, [x5], 16
        LDR     d1,  [x9], 8
        LDR     d2, [x10], 8
        LDR     d3, [x11], 8
        LDR     d4, [x12], 8
        LDR     d5,  [x4], 8
        LDR     q18, [x5], 16
        LDR     q19, [x5], 16
        SUBS    x0, x0, 8
        FMLA    v20.8h, v16.8h,  v0.h[0]
        FMLA    v22.8h, v16.8h,  v1.h[0]
        FMLA    v24.8h, v16.8h,  v2.h[0]
        FMLA    v26.8h, v16.8h,  v3.h[0]
        FMLA    v28.8h, v16.8h,  v4.h[0]
        FMLA    v30.8h, v16.8h,  v5.h[0]
        FMLA    v20.8h, v17.8h,  v0.h[1]
        FMLA    v22.8h, v17.8h,  v1.h[1]
        FMLA    v24.8h, v17.8h,  v2.h[1]
        FMLA    v26.8h, v17.8h,  v3.h[1]
        FMLA    v28.8h, v17.8h,  v4.h[1]
        FMLA    v30.8h, v17.8h,  v5.h[1]

        FMLA    v20.8h, v18.8h,  v0.h[2]
        FMLA    v22.8h, v18.8h,  v1.h[2]
        FMLA    v24.8h, v18.8h,  v2.h[2]
        FMLA    v26.8h, v18.8h,  v3.h[2]
        FMLA    v28.8h, v18.8h,  v4.h[2]
        FMLA    v30.8h, v18.8h,  v5.h[2]
        FMLA    v20.8h, v19.8h,  v0.h[3]
        FMLA    v22.8h, v19.8h,  v1.h[3]
        FMLA    v24.8h, v19.8h,  v2.h[3]
        FMLA    v26.8h, v19.8h,  v3.h[3]
        FMLA    v28.8h, v19.8h,  v4.h[3]
        FMLA    v30.8h, v19.8h,  v5.h[3]
        B.HS    1b

        # Is there a remainder?- 2 halffloats of A (4 bytes)
        TBNZ    x0, 2, 4f
        # Is there a remainder?- 1 halffloat of A (2 bytes)
        TBNZ    x0, 1, 5f
2:
        # Clamp
        DUP     v4.8h, v6.h[0]
        DUP     v5.8h, v6.h[1]
        FMAX    v20.8h, v20.8h, v4.8h
        FMAX    v22.8h, v22.8h, v4.8h
        FMAX    v24.8h, v24.8h, v4.8h
        FMAX    v26.8h, v26.8h, v4.8h
        FMAX    v28.8h, v28.8h, v4.8h
        FMAX    v30.8h, v30.8h, v4.8h
        SUBS    x1, x1, 8
        FMIN    v20.8h, v20.8h, v5.8h
        FMIN    v22.8h, v22.8h, v5.8h
        FMIN    v24.8h, v24.8h, v5.8h
        FMIN    v26.8h, v26.8h, v5.8h
        FMIN    v28.8h, v28.8h, v5.8h
        FMIN    v30.8h, v30.8h, v5.8h

        # Store full 6 x 8
        B.LO    6f

        $if INC:
          ST1     {v30.16b},  [x7], x8
          SUB     x3,  x3, x2             // a0 -= kc
          ST1     {v28.16b}, [x13], x8
          SUB     x9,  x9, x2             // a1 -= kc
          ST1     {v26.16b}, [x14], x8
          SUB     x10, x10, x2            // a2 -= kc
          ST1     {v24.16b}, [x17], x8
          SUB     x11, x11, x2            // a3 -= kc
          ST1     {v22.16b}, [x16], x8
          SUB     x12, x12, x2            // a4 -= kc
          ST1     {v20.16b},  [x6], x8
          SUB     x4,  x4, x2             // a5 -= kc
        $else:
          ST1     {v20.16b},  [x6], x8
          SUB     x3,  x3, x2             // a0 -= kc
          ST1     {v22.16b}, [x16], x8
          SUB     x9,  x9, x2             // a1 -= kc
          ST1     {v24.16b}, [x17], x8
          SUB     x10, x10, x2            // a2 -= kc
          ST1     {v26.16b}, [x14], x8
          SUB     x11, x11, x2            // a3 -= kc
          ST1     {v28.16b}, [x13], x8
          SUB     x12, x12, x2            // a4 -= kc
          ST1     {v30.16b},  [x7], x8
          SUB     x4,  x4, x2             // a5 -= kc

        B.HI    0b
        RET

3:
        TBZ     x0, 2, 5f
4:
        # Remainder- 2 halffloats of A (4 bytes)
        LDR     s0,  [x3], 4
        LDR     q16, [x5], 16
        LDR     q17, [x5], 16
        LDR     s1,  [x9], 4
        LDR     s2, [x10], 4
        LDR     s3, [x11], 4
        LDR     s4, [x12], 4
        LDR     s5,  [x4], 4

        FMLA    v20.8h, v16.8h,  v0.h[0]
        FMLA    v22.8h, v16.8h,  v1.h[0]
        FMLA    v24.8h, v16.8h,  v2.h[0]
        FMLA    v26.8h, v16.8h,  v3.h[0]
        FMLA    v28.8h, v16.8h,  v4.h[0]
        FMLA    v30.8h, v16.8h,  v5.h[0]

        FMLA    v20.8h, v17.8h,  v0.h[1]
        FMLA    v22.8h, v17.8h,  v1.h[1]
        FMLA    v24.8h, v17.8h,  v2.h[1]
        FMLA    v26.8h, v17.8h,  v3.h[1]
        FMLA    v28.8h, v17.8h,  v4.h[1]
        FMLA    v30.8h, v17.8h,  v5.h[1]
        TBZ     x0, 1, 2b

5:
        # Remainder- 1 halffloat of A (2 bytes)
        LDR     h0,  [x3], 2
        LDR     q16,  [x5], 16
        LDR     h1,  [x9], 2
        LDR     h2, [x10], 2
        LDR     h3, [x11], 2
        LDR     h4, [x12], 2
        LDR     h5,  [x4], 2
        FMLA    v20.8h, v16.8h,  v0.h[0]
        FMLA    v22.8h, v16.8h,  v1.h[0]
        FMLA    v24.8h, v16.8h,  v2.h[0]
        FMLA    v26.8h, v16.8h,  v3.h[0]
        FMLA    v28.8h, v16.8h,  v4.h[0]
        FMLA    v30.8h, v16.8h,  v5.h[0]
        B       2b

        # Store odd width
6:
        TBZ     x1, 2, 7f
        $if INC:
          STR     d30,  [x7], 8
          STR     d28, [x13], 8
          DUP     d30, v30.d[1]
          DUP     d28, v28.d[1]
          STR     d26, [x14], 8
          STR     d24, [x17], 8
          DUP     d26, v26.d[1]
          DUP     d24, v24.d[1]
          STR     d22, [x16], 8
          STR     d20,  [x6], 8
          DUP     d22, v22.d[1]
          DUP     d20, v20.d[1]
        $else:
          STR     d20,  [x6], 8
          STR     d22, [x16], 8
          DUP     d20, v20.d[1]
          DUP     d22, v22.d[1]
          STR     d24, [x17], 8
          STR     d26, [x14], 8
          DUP     d24, v24.d[1]
          DUP     d26, v26.d[1]
          STR     d28, [x13], 8
          STR     d30,  [x7], 8
          DUP     d28, v28.d[1]
          DUP     d30, v30.d[1]

7:
        TBZ     x1, 1, 8f
        $if INC:
          STR     s30,  [x7], 4
          STR     s28, [x13], 4
          DUP     s30, v30.s[1]
          DUP     s28, v28.s[1]
          STR     s26, [x14], 4
          STR     s24, [x17], 4
          DUP     s26, v26.s[1]
          DUP     s24, v24.s[1]
          STR     s22, [x16], 4
          STR     s20,  [x6], 4
          DUP     s22, v22.s[1]
          DUP     s20, v20.s[1]
        $else:
          STR     s20,  [x6], 4
          STR     s22, [x16], 4
          DUP     s20, v20.s[1]
          DUP     s22, v22.s[1]
          STR     s24, [x17], 4
          STR     s26, [x14], 4
          DUP     s24, v24.s[1]
          DUP     s26, v26.s[1]
          STR     s28, [x13], 4
          STR     s30,  [x7], 4
          DUP     s28, v28.s[1]
          DUP     s30, v30.s[1]

8:
        TBZ     x1, 0, 9f
        $if INC:
          STR     h30,  [x7]
          STR     h28, [x13]
          STR     h26, [x14]
          STR     h24, [x17]
          STR     h22, [x16]
          STR     h20,  [x6]
        $else:
          STR     h20,  [x6]
          STR     h22, [x16]
          STR     h24, [x17]
          STR     h26, [x14]
          STR     h28, [x13]
          STR     h30,  [x7]
9:
        RET

END_FUNCTION xnn_f16_gemm${"inc" if INC else ""}_minmax_ukernel_6x8__aarch64_neonfp16arith_ld64

#ifdef __ELF__
.section ".note.GNU-stack","",%progbits
#endif