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tcg/riscv: Add the add2 and sub2 instructions

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Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <5665a57809e32b35775e8e98fdab898853af37b8.1545246859.git.alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Alistair Francis 2018-12-19 19:18:49 +00:00 committed by Richard Henderson
parent 61535d4988
commit 28ca738e9d
1 changed files with 55 additions and 0 deletions
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55
tcg/riscv/tcg-target.inc.c
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@ -695,3 +695,58 @@ static bool tcg_out_sti(TCGContext *s, TCGType type, TCGArg val,
}
return false;
}
static void tcg_out_addsub2(TCGContext *s,
TCGReg rl, TCGReg rh,
TCGReg al, TCGReg ah,
TCGArg bl, TCGArg bh,
bool cbl, bool cbh, bool is_sub, bool is32bit)
{
const RISCVInsn opc_add = is32bit ? OPC_ADDW : OPC_ADD;
const RISCVInsn opc_addi = is32bit ? OPC_ADDIW : OPC_ADDI;
const RISCVInsn opc_sub = is32bit ? OPC_SUBW : OPC_SUB;
TCGReg th = TCG_REG_TMP1;
/* If we have a negative constant such that negating it would
make the high part zero, we can (usually) eliminate one insn. */
if (cbl && cbh && bh == -1 && bl != 0) {
bl = -bl;
bh = 0;
is_sub = !is_sub;
}
/* By operating on the high part first, we get to use the final
carry operation to move back from the temporary. */
if (!cbh) {
tcg_out_opc_reg(s, (is_sub ? opc_sub : opc_add), th, ah, bh);
} else if (bh != 0 || ah == rl) {
tcg_out_opc_imm(s, opc_addi, th, ah, (is_sub ? -bh : bh));
} else {
th = ah;
}
/* Note that tcg optimization should eliminate the bl == 0 case. */
if (is_sub) {
if (cbl) {
tcg_out_opc_imm(s, OPC_SLTIU, TCG_REG_TMP0, al, bl);
tcg_out_opc_imm(s, opc_addi, rl, al, -bl);
} else {
tcg_out_opc_reg(s, OPC_SLTU, TCG_REG_TMP0, al, bl);
tcg_out_opc_reg(s, opc_sub, rl, al, bl);
}
tcg_out_opc_reg(s, opc_sub, rh, th, TCG_REG_TMP0);
} else {
if (cbl) {
tcg_out_opc_imm(s, opc_addi, rl, al, bl);
tcg_out_opc_imm(s, OPC_SLTIU, TCG_REG_TMP0, rl, bl);
} else if (rl == al && rl == bl) {
tcg_out_opc_imm(s, OPC_SLTI, TCG_REG_TMP0, al, 0);
tcg_out_opc_reg(s, opc_addi, rl, al, bl);
} else {
tcg_out_opc_reg(s, opc_add, rl, al, bl);
tcg_out_opc_reg(s, OPC_SLTU, TCG_REG_TMP0,
rl, (rl == bl ? al : bl));
}
tcg_out_opc_reg(s, opc_add, rh, th, TCG_REG_TMP0);
}
}