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sh2 drc, improve T bit propagation

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kub 2020-10-10 09:44:15 +02:00
parent 0de604b1ff
commit b286d66f7b
1 changed files with 8 additions and 6 deletions
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14
cpu/sh2/compiler.c
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@ -6847,7 +6847,7 @@ end:
// 2nd pass: some analysis
lowest_literal = end_literals = lowest_mova = 0;
t = T_UNKNOWN;
t = T_UNKNOWN; // T flag state
last_btarget = 0;
op = 0; // delay/poll insns counter
is_divop = 0; // divide op insns counter
@ -6857,7 +6857,7 @@ end:
crc += FETCH_OP(pc);
// propagate T (TODO: DIV0U)
if ((op_flags[i] & OF_BTARGET) || (opd->dest & BITMASK1(SHR_T)))
if (op_flags[i] & OF_BTARGET)
t = T_UNKNOWN;
if ((opd->op == OP_BRANCH_CT && t == T_SET) ||
@ -6867,10 +6867,12 @@ end:
} else if ((opd->op == OP_BRANCH_CT && t == T_CLEAR) ||
(opd->op == OP_BRANCH_CF && t == T_SET))
opd->op = OP_BRANCH_N;
else if ((opd->op == OP_SETCLRT && !opd->imm) || opd->op == OP_BRANCH_CT)
t = T_CLEAR;
else if ((opd->op == OP_SETCLRT && opd->imm) || opd->op == OP_BRANCH_CF)
t = T_SET;
else if (OP_ISBRACND(opd->op))
t = (opd->op == OP_BRANCH_CF ? T_SET : T_CLEAR);
else if (opd->op == OP_SETCLRT)
t = (opd->imm ? T_SET : T_CLEAR);
else if (opd->dest & BITMASK1(SHR_T))
t = T_UNKNOWN;
// "overscan" detection: unreachable code after unconditional branch
// this can happen if the insn after a forward branch isn't a local target