dranke/upkr
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more rv optimizations, rv32imc now 204b

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Dennis Ranke
2022-10-03 15:38:43 +02:00
parent a46eb0e7f5
commit 83c023de45
1 changed files with 46 additions and 53 deletions
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99
asm_unpackers/unpack_riscv.S
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@@ -33,7 +33,7 @@ upkr_unpack:
.Lfinished_offset:
addi x14, x14, 64
jal upkr_decode_number
jalr ra // jal upkr_decode_number
1:
add x14, x10, t0
lbu x14, (x14)
@@ -56,7 +56,7 @@ upkr_unpack:
.Lread_offset_inc_x14:
addi x14, x14, 1
.Lread_offset:
jal upkr_decode_number
jalr ra // jal upkr_decode_number
addi t0, x9, 1
bnez t0, .Lfinished_offset
.Ldone:
@@ -64,6 +64,50 @@ upkr_unpack:
mv x9, t6
jr t4
upkr_load_byte:
lbu x15, 0(x11)
addi x11, x11, 1
slli x13, x13, 8
add x13, x13, x15
// x8 prob array ptr
// x11 in ptr
// x13 state
// x14 context index
// return:
// x14 context index + 1
// x15 decoded bit
upkr_decode_bit:
srli x15, x13, 12
beqz x15, upkr_load_byte
addi x14, x14, 1
sub t2, sp, x14
lbu x12, 0(t2)
andi x8, x13, 255
sltu x15, x8, x12
beqz x15, 1f
xori x12, x12, 255
addi x12, x12, 1
1:
srli x8, x13, 8
addi x8, x8, 1
sub x8, x8, x15
mul x8, x8, x12
sub x13, x13, x8
addi x8, x12, 8
srli x8, x8, 4
sub x12, x12, x8
beqz x15, 1f
sub x12, x0, x12
1:
sb x12, 0(t2)
jalr ra
// x14 context index
// return: x9 negtive decoded number
upkr_decode_number:
@@ -85,54 +129,3 @@ upkr_decode_number:
mv x14, t5
jr t3
upkr_load_byte:
lbu x15, 0(x11)
addi x11, x11, 1
slli x13, x13, 8
add x13, x13, x15
// x8 prob array ptr
// x11 in ptr
// x13 state
// x14 context index
// return:
// x14 context index + 1
// x15 decoded bit
upkr_decode_bit:
srli x15, x13, 12
beqz x15, upkr_load_byte
addi x14, x14, 1
sub sp, sp, x14
lbu x12, 0(sp)
andi x8, x13, 255
sltu x15, x8, x12
srli x13, x13, 8
beqz x15, .Lelse
mul x13, x13, x12
add x13, x13, x8
li x8, 256 + 8
sub x8, x8, x12
srli x8, x8, 4
add x12, x12, x8
j .Lendif
.Lelse:
li x16, 256
sub x16, x16, x12
mul x13, x13, x16
add x13, x13, x8
sub x13, x13, x12
addi x8, x12, 8
srli x8, x8, 4
sub x12, x12, x8
.Lendif:
sb x12, 0(sp)
add sp, sp, x14
ret