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target/riscv: Clean up division helpers 

Utilize the condition in the movcond more; this allows some of
the setcond that were feeding into movcond to be removed.
Do not write into source1 and source2.  Re-name "condN" to "tempN"
and use the temporaries for more than holding conditions.

Tested-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210823195529.560295-4-richard.henderson@linaro.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
master
Richard Henderson 2021-08-23 12:55:08 -07:00 committed by Alistair Francis
parent 9b17ae9c6a
commit 4a083b563a
1 changed files with 84 additions and 76 deletions
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160
target/riscv/translate.c
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@ -213,106 +213,114 @@ static void gen_mulhsu(TCGv ret, TCGv arg1, TCGv arg2)
static void gen_div(TCGv ret, TCGv source1, TCGv source2) static void gen_div(TCGv ret, TCGv source1, TCGv source2)
{ {
TCGv cond1, cond2, zeroreg, resultopt1; TCGv temp1, temp2, zero, one, mone, min;
temp1 = tcg_temp_new();
temp2 = tcg_temp_new();
zero = tcg_constant_tl(0);
one = tcg_constant_tl(1);
mone = tcg_constant_tl(-1);
min = tcg_constant_tl(1ull << (TARGET_LONG_BITS - 1));
/* /*
* Handle by altering args to tcg_gen_div to produce req'd results: * If overflow, set temp2 to 1, else source2.
* For overflow: want source1 in source1 and 1 in source2 * This produces the required result of min.
* For div by zero: want -1 in source1 and 1 in source2 -> -1 result
*/ */
cond1 = tcg_temp_new(); tcg_gen_setcond_tl(TCG_COND_EQ, temp1, source1, min);
cond2 = tcg_temp_new(); tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, mone);
zeroreg = tcg_constant_tl(0); tcg_gen_and_tl(temp1, temp1, temp2);
resultopt1 = tcg_temp_new(); tcg_gen_movcond_tl(TCG_COND_NE, temp2, temp1, zero, one, source2);
tcg_gen_movi_tl(resultopt1, (target_ulong)-1); /*
tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, (target_ulong)(~0L)); * If div by zero, set temp1 to -1 and temp2 to 1 to
tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source1, * produce the required result of -1.
((target_ulong)1) << (TARGET_LONG_BITS - 1)); */
tcg_gen_and_tl(cond1, cond1, cond2); /* cond1 = overflow */ tcg_gen_movcond_tl(TCG_COND_EQ, temp1, source2, zero, mone, source1);
tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, 0); /* cond2 = div 0 */ tcg_gen_movcond_tl(TCG_COND_EQ, temp2, source2, zero, one, temp2);
/* if div by zero, set source1 to -1, otherwise don't change */
tcg_gen_movcond_tl(TCG_COND_EQ, source1, cond2, zeroreg, source1,
resultopt1);
/* if overflow or div by zero, set source2 to 1, else don't change */
tcg_gen_or_tl(cond1, cond1, cond2);
tcg_gen_movi_tl(resultopt1, (target_ulong)1);
tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2,
resultopt1);
tcg_gen_div_tl(ret, source1, source2);
tcg_temp_free(cond1); tcg_gen_div_tl(ret, temp1, temp2);
tcg_temp_free(cond2);
tcg_temp_free(resultopt1); tcg_temp_free(temp1);
tcg_temp_free(temp2);
} }
static void gen_divu(TCGv ret, TCGv source1, TCGv source2) static void gen_divu(TCGv ret, TCGv source1, TCGv source2)
{ {
TCGv cond1, zeroreg, resultopt1; TCGv temp1, temp2, zero, one, max;
cond1 = tcg_temp_new();
zeroreg = tcg_constant_tl(0); temp1 = tcg_temp_new();
resultopt1 = tcg_temp_new(); temp2 = tcg_temp_new();
zero = tcg_constant_tl(0);
one = tcg_constant_tl(1);
max = tcg_constant_tl(~0);
tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0); /*
tcg_gen_movi_tl(resultopt1, (target_ulong)-1); * If div by zero, set temp1 to max and temp2 to 1 to
tcg_gen_movcond_tl(TCG_COND_EQ, source1, cond1, zeroreg, source1, * produce the required result of max.
resultopt1); */
tcg_gen_movi_tl(resultopt1, (target_ulong)1); tcg_gen_movcond_tl(TCG_COND_EQ, temp1, source2, zero, max, source1);
tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2, tcg_gen_movcond_tl(TCG_COND_EQ, temp2, source2, zero, one, source2);
resultopt1); tcg_gen_divu_tl(ret, temp1, temp2);
tcg_gen_divu_tl(ret, source1, source2);
tcg_temp_free(cond1); tcg_temp_free(temp1);
tcg_temp_free(resultopt1); tcg_temp_free(temp2);
} }
static void gen_rem(TCGv ret, TCGv source1, TCGv source2) static void gen_rem(TCGv ret, TCGv source1, TCGv source2)
{ {
TCGv cond1, cond2, zeroreg, resultopt1; TCGv temp1, temp2, zero, one, mone, min;
cond1 = tcg_temp_new(); temp1 = tcg_temp_new();
cond2 = tcg_temp_new(); temp2 = tcg_temp_new();
zeroreg = tcg_constant_tl(0); zero = tcg_constant_tl(0);
resultopt1 = tcg_temp_new(); one = tcg_constant_tl(1);
mone = tcg_constant_tl(-1);
min = tcg_constant_tl(1ull << (TARGET_LONG_BITS - 1));
tcg_gen_movi_tl(resultopt1, 1L); /*
tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, (target_ulong)-1); * If overflow, set temp1 to 0, else source1.
tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source1, * This avoids a possible host trap, and produces the required result of 0.
(target_ulong)1 << (TARGET_LONG_BITS - 1)); */
tcg_gen_and_tl(cond2, cond1, cond2); /* cond1 = overflow */ tcg_gen_setcond_tl(TCG_COND_EQ, temp1, source1, min);
tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0); /* cond2 = div 0 */ tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, mone);
/* if overflow or div by zero, set source2 to 1, else don't change */ tcg_gen_and_tl(temp1, temp1, temp2);
tcg_gen_or_tl(cond2, cond1, cond2); tcg_gen_movcond_tl(TCG_COND_NE, temp1, temp1, zero, zero, source1);
tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond2, zeroreg, source2,
resultopt1);
tcg_gen_rem_tl(resultopt1, source1, source2);
/* if div by zero, just return the original dividend */
tcg_gen_movcond_tl(TCG_COND_EQ, ret, cond1, zeroreg, resultopt1,
source1);
tcg_temp_free(cond1); /*
tcg_temp_free(cond2); * If div by zero, set temp2 to 1, else source2.
tcg_temp_free(resultopt1); * This avoids a possible host trap, but produces an incorrect result.
*/
tcg_gen_movcond_tl(TCG_COND_EQ, temp2, source2, zero, one, source2);
tcg_gen_rem_tl(temp1, temp1, temp2);
/* If div by zero, the required result is the original dividend. */
tcg_gen_movcond_tl(TCG_COND_EQ, ret, source2, zero, source1, temp1);
tcg_temp_free(temp1);
tcg_temp_free(temp2);
} }
static void gen_remu(TCGv ret, TCGv source1, TCGv source2) static void gen_remu(TCGv ret, TCGv source1, TCGv source2)
{ {
TCGv cond1, zeroreg, resultopt1; TCGv temp, zero, one;
cond1 = tcg_temp_new();
zeroreg = tcg_constant_tl(0);
resultopt1 = tcg_temp_new();
tcg_gen_movi_tl(resultopt1, (target_ulong)1); temp = tcg_temp_new();
tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0); zero = tcg_constant_tl(0);
tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2, one = tcg_constant_tl(1);
resultopt1);
tcg_gen_remu_tl(resultopt1, source1, source2);
/* if div by zero, just return the original dividend */
tcg_gen_movcond_tl(TCG_COND_EQ, ret, cond1, zeroreg, resultopt1,
source1);
tcg_temp_free(cond1); /*
tcg_temp_free(resultopt1); * If div by zero, set temp to 1, else source2.
* This avoids a possible host trap, but produces an incorrect result.
*/
tcg_gen_movcond_tl(TCG_COND_EQ, temp, source2, zero, one, source2);
tcg_gen_remu_tl(temp, source1, temp);
/* If div by zero, the required result is the original dividend. */
tcg_gen_movcond_tl(TCG_COND_EQ, ret, source2, zero, source1, temp);
tcg_temp_free(temp);
} }
static void gen_jal(DisasContext *ctx, int rd, target_ulong imm) static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)