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Re: [Qemu-devel] [RFC v6 10/14] softmmu: Simplify helper_*_st_name, wrap
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [RFC v6 10/14] softmmu: Simplify helper_*_st_name, wrap unaligned code |
Date: |
Thu, 07 Jan 2016 14:46:12 +0000 |
User-agent: |
mu4e 0.9.15; emacs 25.1.50.8 |
Alvise Rigo <address@hidden> writes:
> Attempting to simplify the helper_*_st_name, wrap the
> do_unaligned_access code into an inline function.
> Remove also the goto statement.
As I said in the other thread I think these sort of clean-ups can come
before the ll/sc implementations and potentially get merged ahead of the
rest of it.
>
> Suggested-by: Jani Kokkonen <address@hidden>
> Suggested-by: Claudio Fontana <address@hidden>
> Signed-off-by: Alvise Rigo <address@hidden>
> ---
> softmmu_template.h | 96
> ++++++++++++++++++++++++++++++++++--------------------
> 1 file changed, 60 insertions(+), 36 deletions(-)
>
> diff --git a/softmmu_template.h b/softmmu_template.h
> index d3d5902..92f92b1 100644
> --- a/softmmu_template.h
> +++ b/softmmu_template.h
> @@ -370,6 +370,32 @@ static inline void glue(io_write, SUFFIX)(CPUArchState
> *env,
> iotlbentry->attrs);
> }
>
> +static inline void glue(helper_le_st_name, _do_unl_access)(CPUArchState *env,
> + DATA_TYPE val,
> + target_ulong addr,
> + TCGMemOpIdx oi,
> + unsigned mmu_idx,
> + uintptr_t retaddr)
> +{
> + int i;
> +
> + if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
> + cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
> + mmu_idx, retaddr);
> + }
> + /* XXX: not efficient, but simple */
> + /* Note: relies on the fact that tlb_fill() does not remove the
> + * previous page from the TLB cache. */
> + for (i = DATA_SIZE - 1; i >= 0; i--) {
> + /* Little-endian extract. */
> + uint8_t val8 = val >> (i * 8);
> + /* Note the adjustment at the beginning of the function.
> + Undo that for the recursion. */
> + glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
> + oi, retaddr + GETPC_ADJ);
> + }
> +}
There is still duplication of 99% of the code here which is silly given
the compiler inlines the code anyway. If we gave the helper a more
generic name and passed the endianess in via args I would hope the
compiler did the sensible thing and constant fold the code. Something
like:
static inline void glue(helper_generic_st_name, _do_unl_access)
(CPUArchState *env,
bool little_endian,
DATA_TYPE val,
target_ulong addr,
TCGMemOpIdx oi,
unsigned mmu_idx,
uintptr_t retaddr)
{
int i;
if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
mmu_idx, retaddr);
}
/* Note: relies on the fact that tlb_fill() does not remove the
* previous page from the TLB cache. */
for (i = DATA_SIZE - 1; i >= 0; i--) {
if (little_endian) {
/* Little-endian extract. */
uint8_t val8 = val >> (i * 8);
} else {
/* Big-endian extract. */
uint8_t val8 = val >> (((DATA_SIZE - 1) * 8) - (i * 8));
}
/* Note the adjustment at the beginning of the function.
Undo that for the recursion. */
glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
oi, retaddr + GETPC_ADJ);
}
}
> +
> void helper_le_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val,
> TCGMemOpIdx oi, uintptr_t retaddr)
> {
> @@ -433,7 +459,8 @@ void helper_le_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> return;
> } else {
> if ((addr & (DATA_SIZE - 1)) != 0) {
> - goto do_unaligned_access;
> + glue(helper_le_st_name, _do_unl_access)(env, val, addr,
> mmu_idx,
> + oi, retaddr);
> }
> iotlbentry = &env->iotlb[mmu_idx][index];
>
> @@ -449,23 +476,8 @@ void helper_le_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> if (DATA_SIZE > 1
> && unlikely((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1
> >= TARGET_PAGE_SIZE)) {
> - int i;
> - do_unaligned_access:
> - if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
> - cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
> - mmu_idx, retaddr);
> - }
> - /* XXX: not efficient, but simple */
> - /* Note: relies on the fact that tlb_fill() does not remove the
> - * previous page from the TLB cache. */
> - for (i = DATA_SIZE - 1; i >= 0; i--) {
> - /* Little-endian extract. */
> - uint8_t val8 = val >> (i * 8);
> - /* Note the adjustment at the beginning of the function.
> - Undo that for the recursion. */
> - glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
> - oi, retaddr + GETPC_ADJ);
> - }
> + glue(helper_le_st_name, _do_unl_access)(env, val, addr, oi, mmu_idx,
> + retaddr);
> return;
> }
>
> @@ -485,6 +497,32 @@ void helper_le_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> }
>
> #if DATA_SIZE > 1
> +static inline void glue(helper_be_st_name, _do_unl_access)(CPUArchState *env,
> + DATA_TYPE val,
> + target_ulong addr,
> + TCGMemOpIdx oi,
> + unsigned mmu_idx,
> + uintptr_t retaddr)
> +{
> + int i;
> +
> + if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
> + cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
> + mmu_idx, retaddr);
> + }
> + /* XXX: not efficient, but simple */
> + /* Note: relies on the fact that tlb_fill() does not remove the
> + * previous page from the TLB cache. */
> + for (i = DATA_SIZE - 1; i >= 0; i--) {
> + /* Big-endian extract. */
> + uint8_t val8 = val >> (((DATA_SIZE - 1) * 8) - (i * 8));
> + /* Note the adjustment at the beginning of the function.
> + Undo that for the recursion. */
> + glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
> + oi, retaddr + GETPC_ADJ);
> + }
> +}
Not that it matters if you combine to two as suggested because anything
not called shouldn't generate the code.
> void helper_be_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val,
> TCGMemOpIdx oi, uintptr_t retaddr)
> {
> @@ -548,7 +586,8 @@ void helper_be_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> return;
> } else {
> if ((addr & (DATA_SIZE - 1)) != 0) {
> - goto do_unaligned_access;
> + glue(helper_be_st_name, _do_unl_access)(env, val, addr,
> mmu_idx,
> + oi, retaddr);
> }
> iotlbentry = &env->iotlb[mmu_idx][index];
>
> @@ -564,23 +603,8 @@ void helper_be_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> if (DATA_SIZE > 1
> && unlikely((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1
> >= TARGET_PAGE_SIZE)) {
> - int i;
> - do_unaligned_access:
> - if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
> - cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
> - mmu_idx, retaddr);
> - }
> - /* XXX: not efficient, but simple */
> - /* Note: relies on the fact that tlb_fill() does not remove the
> - * previous page from the TLB cache. */
> - for (i = DATA_SIZE - 1; i >= 0; i--) {
> - /* Big-endian extract. */
> - uint8_t val8 = val >> (((DATA_SIZE - 1) * 8) - (i * 8));
> - /* Note the adjustment at the beginning of the function.
> - Undo that for the recursion. */
> - glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
> - oi, retaddr + GETPC_ADJ);
> - }
> + glue(helper_be_st_name, _do_unl_access)(env, val, addr, oi, mmu_idx,
> + retaddr);
> return;
> }
--
Alex Bennée
- Re: [Qemu-devel] [RFC v6 10/14] softmmu: Simplify helper_*_st_name, wrap unaligned code,
Alex Bennée <=