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tcg/arm: Fix double-word comparisons 

The code sequence we were generating was only good for unsigned
comparisons.  For signed comparisions, use the sequence from gcc.

Fixes booting of ppc64 firmware, with a patch changing the code
sequence for ppc comparisons.

Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2018-01-15 13:01:37 -08:00
parent aae39d24a3
commit 7170ac3313
1 changed files with 60 additions and 26 deletions
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86
tcg/arm/tcg-target.inc.c
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@ -1103,6 +1103,56 @@ static inline void tcg_out_mb(TCGContext *s, TCGArg a0)
}
}
static TCGCond tcg_out_cmp2(TCGContext *s, const TCGArg *args,
const int *const_args)
{
TCGReg al = args[0];
TCGReg ah = args[1];
TCGArg bl = args[2];
TCGArg bh = args[3];
TCGCond cond = args[4];
int const_bl = const_args[2];
int const_bh = const_args[3];
switch (cond) {
case TCG_COND_EQ:
case TCG_COND_NE:
case TCG_COND_LTU:
case TCG_COND_LEU:
case TCG_COND_GTU:
case TCG_COND_GEU:
/* We perform a conditional comparision. If the high half is
equal, then overwrite the flags with the comparison of the
low half. The resulting flags cover the whole. */
tcg_out_dat_rI(s, COND_AL, ARITH_CMP, 0, ah, bh, const_bh);
tcg_out_dat_rI(s, COND_EQ, ARITH_CMP, 0, al, bl, const_bl);
return cond;
case TCG_COND_LT:
case TCG_COND_GE:
/* We perform a double-word subtraction and examine the result.
We do not actually need the result of the subtract, so the
low part "subtract" is a compare. For the high half we have
no choice but to compute into a temporary. */
tcg_out_dat_rI(s, COND_AL, ARITH_CMP, 0, al, bl, const_bl);
tcg_out_dat_rI(s, COND_AL, ARITH_SBC | TO_CPSR,
TCG_REG_TMP, ah, bh, const_bh);
return cond;
case TCG_COND_LE:
case TCG_COND_GT:
/* Similar, but with swapped arguments, via reversed subtract. */
tcg_out_dat_rI(s, COND_AL, ARITH_RSB | TO_CPSR,
TCG_REG_TMP, al, bl, const_bl);
tcg_out_dat_rI(s, COND_AL, ARITH_RSC | TO_CPSR,
TCG_REG_TMP, ah, bh, const_bh);
return tcg_swap_cond(cond);
default:
g_assert_not_reached();
}
}
#ifdef CONFIG_SOFTMMU
#include "tcg-ldst.inc.c"
@ -1964,22 +2014,6 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
tcg_out_goto_label(s, tcg_cond_to_arm_cond[args[2]],
arg_label(args[3]));
break;
case INDEX_op_brcond2_i32:
/* The resulting conditions are:
* TCG_COND_EQ --> a0 == a2 && a1 == a3,
* TCG_COND_NE --> (a0 != a2 && a1 == a3) || a1 != a3,
* TCG_COND_LT(U) --> (a0 < a2 && a1 == a3) || a1 < a3,
* TCG_COND_GE(U) --> (a0 >= a2 && a1 == a3) || (a1 >= a3 && a1 != a3),
* TCG_COND_LE(U) --> (a0 <= a2 && a1 == a3) || (a1 <= a3 && a1 != a3),
* TCG_COND_GT(U) --> (a0 > a2 && a1 == a3) || a1 > a3,
*/
tcg_out_dat_rIN(s, COND_AL, ARITH_CMP, ARITH_CMN, 0,
args[1], args[3], const_args[3]);
tcg_out_dat_rIN(s, COND_EQ, ARITH_CMP, ARITH_CMN, 0,
args[0], args[2], const_args[2]);
tcg_out_goto_label(s, tcg_cond_to_arm_cond[args[4]],
arg_label(args[5]));
break;
case INDEX_op_setcond_i32:
tcg_out_dat_rIN(s, COND_AL, ARITH_CMP, ARITH_CMN, 0,
args[1], args[2], const_args[2]);
@ -1988,15 +2022,15 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
tcg_out_dat_imm(s, tcg_cond_to_arm_cond[tcg_invert_cond(args[3])],
ARITH_MOV, args[0], 0, 0);
break;
case INDEX_op_brcond2_i32:
c = tcg_out_cmp2(s, args, const_args);
tcg_out_goto_label(s, tcg_cond_to_arm_cond[c], arg_label(args[5]));
break;
case INDEX_op_setcond2_i32:
/* See brcond2_i32 comment */
tcg_out_dat_rIN(s, COND_AL, ARITH_CMP, ARITH_CMN, 0,
args[2], args[4], const_args[4]);
tcg_out_dat_rIN(s, COND_EQ, ARITH_CMP, ARITH_CMN, 0,
args[1], args[3], const_args[3]);
tcg_out_dat_imm(s, tcg_cond_to_arm_cond[args[5]],
ARITH_MOV, args[0], 0, 1);
tcg_out_dat_imm(s, tcg_cond_to_arm_cond[tcg_invert_cond(args[5])],
c = tcg_out_cmp2(s, args + 1, const_args + 1);
tcg_out_dat_imm(s, tcg_cond_to_arm_cond[c], ARITH_MOV, args[0], 0, 1);
tcg_out_dat_imm(s, tcg_cond_to_arm_cond[tcg_invert_cond(c)],
ARITH_MOV, args[0], 0, 0);
break;
@ -2093,9 +2127,9 @@ static const TCGTargetOpDef *tcg_target_op_def(TCGOpcode op)
static const TCGTargetOpDef sub2
= { .args_ct_str = { "r", "r", "rI", "rI", "rIN", "rIK" } };
static const TCGTargetOpDef br2
= { .args_ct_str = { "r", "r", "rIN", "rIN" } };
= { .args_ct_str = { "r", "r", "rI", "rI" } };
static const TCGTargetOpDef setc2
= { .args_ct_str = { "r", "r", "r", "rIN", "rIN" } };
= { .args_ct_str = { "r", "r", "r", "rI", "rI" } };
switch (op) {
case INDEX_op_goto_ptr: