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Re: [Qemu-devel] [PATCH v5 13/19] tcg-arm: Cleanup multiply subroutines
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH v5 13/19] tcg-arm: Cleanup multiply subroutines |
Date: |
Mon, 22 Apr 2013 11:07:40 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Sun, Mar 31, 2013 at 03:34:59PM -0700, Richard Henderson wrote:
> Make the code more readable by only having one copy of the magic
> numbers, swapping registers as needed prior to that. Speed the
> compiler by not applying the rd == rn avoidance for v6 or later.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> tcg/arm/tcg-target.c | 85
> +++++++++++++++++++++++++++-------------------------
> 1 file changed, 45 insertions(+), 40 deletions(-)
>
> diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c
> index 6e1a4b5..24a2354 100644
> --- a/tcg/arm/tcg-target.c
> +++ b/tcg/arm/tcg-target.c
> @@ -542,55 +542,60 @@ static void tcg_out_dat_rIN(TCGContext *s, int cond,
> int opc, int opneg,
> }
> }
>
> -static inline void tcg_out_mul32(TCGContext *s,
> - int cond, int rd, int rs, int rm)
> -{
> - if (rd != rm)
> - tcg_out32(s, (cond << 28) | (rd << 16) | (0 << 12) |
> - (rs << 8) | 0x90 | rm);
> - else if (rd != rs)
> - tcg_out32(s, (cond << 28) | (rd << 16) | (0 << 12) |
> - (rm << 8) | 0x90 | rs);
> - else {
> - tcg_out32(s, (cond << 28) | (TCG_REG_TMP << 16) | (0 << 12) |
> - (rs << 8) | 0x90 | rm);
> - tcg_out_dat_reg(s, cond, ARITH_MOV,
> - rd, 0, TCG_REG_TMP, SHIFT_IMM_LSL(0));
> +static inline void tcg_out_mul32(TCGContext *s, int cond, TCGReg rd,
> + TCGReg rn, TCGReg rm)
> +{
> + /* if ArchVersion() < 6 && d == n then UNPREDICTABLE; */
> + if (!use_armv6_instructions && rd == rn) {
> + if (rd == rm) {
> + /* rd == rn == rm; copy an input to tmp first. */
> + tcg_out_mov_reg(s, cond, TCG_REG_TMP, rn);
> + rm = rn = TCG_REG_TMP;
> + } else {
> + rn = rm;
> + rm = rd;
> + }
> }
> + /* mul */
> + tcg_out32(s, (cond << 28) | 0x90 | (rd << 16) | (rm << 8) | rn);
> }
>
> -static inline void tcg_out_umull32(TCGContext *s,
> - int cond, int rd0, int rd1, int rs, int rm)
> +static inline void tcg_out_umull32(TCGContext *s, int cond, TCGReg rd0,
> + TCGReg rd1, TCGReg rn, TCGReg rm)
> {
> - if (rd0 != rm && rd1 != rm)
> - tcg_out32(s, (cond << 28) | 0x800090 |
> - (rd1 << 16) | (rd0 << 12) | (rs << 8) | rm);
> - else if (rd0 != rs && rd1 != rs)
> - tcg_out32(s, (cond << 28) | 0x800090 |
> - (rd1 << 16) | (rd0 << 12) | (rm << 8) | rs);
> - else {
> - tcg_out_dat_reg(s, cond, ARITH_MOV,
> - TCG_REG_TMP, 0, rm, SHIFT_IMM_LSL(0));
> - tcg_out32(s, (cond << 28) | 0x800090 | TCG_REG_TMP |
> - (rd1 << 16) | (rd0 << 12) | (rs << 8));
> + /* if ArchVersion() < 6 && (dHi == n || dLo == n) then UNPREDICTABLE; */
> + if (!use_armv6_instructions && (rd0 == rn || rd1 == rn)) {
> + if (rd0 == rm || rd1 == rm) {
> + tcg_out_mov_reg(s, cond, TCG_REG_TMP, rn);
> + rn = TCG_REG_TMP;
> + } else {
> + TCGReg t = rn;
> + rn = rm;
> + rm = t;
> + }
> }
> + /* umull */
> + tcg_out32(s, (cond << 28) | 0x00800090 |
> + (rd1 << 16) | (rd0 << 12) | (rm << 8) | rn);
> }
>
> -static inline void tcg_out_smull32(TCGContext *s,
> - int cond, int rd0, int rd1, int rs, int rm)
> +static inline void tcg_out_smull32(TCGContext *s, int cond, TCGReg rd0,
> + TCGReg rd1, TCGReg rn, TCGReg rm)
> {
> - if (rd0 != rm && rd1 != rm)
> - tcg_out32(s, (cond << 28) | 0xc00090 |
> - (rd1 << 16) | (rd0 << 12) | (rs << 8) | rm);
> - else if (rd0 != rs && rd1 != rs)
> - tcg_out32(s, (cond << 28) | 0xc00090 |
> - (rd1 << 16) | (rd0 << 12) | (rm << 8) | rs);
> - else {
> - tcg_out_dat_reg(s, cond, ARITH_MOV,
> - TCG_REG_TMP, 0, rm, SHIFT_IMM_LSL(0));
> - tcg_out32(s, (cond << 28) | 0xc00090 | TCG_REG_TMP |
> - (rd1 << 16) | (rd0 << 12) | (rs << 8));
> + /* if ArchVersion() < 6 && (dHi == n || dLo == n) then UNPREDICTABLE; */
> + if (!use_armv6_instructions && (rd0 == rn || rd1 == rn)) {
> + if (rd0 == rm || rd1 == rm) {
> + tcg_out_mov_reg(s, cond, TCG_REG_TMP, rn);
> + rn = TCG_REG_TMP;
> + } else {
> + TCGReg t = rn;
> + rn = rm;
> + rm = t;
> + }
> }
> + /* smull */
> + tcg_out32(s, (cond << 28) | 0x00c00090 |
> + (rd1 << 16) | (rd0 << 12) | (rm << 8) | rn);
> }
>
> static inline void tcg_out_sdiv(TCGContext *s, int cond, int rd, int rn, int
> rm)
Reviewed-by: Aurelien Jarno <address@hidden>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net
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