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tcg-mips: Add bswap32u and bswap64
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Without the mips32r2 instructions to perform swapping, bswap is quite large,
dominating the size of each reverse-endian qemu_ld/qemu_st operation.

Create two subroutines in the prologue block.  The subroutines require extra
reserved registers (TCG_TMP[2, 3]).  Using these within qemu_ld means that
we need not place additional restrictions on the qemu_ld outputs.

Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: James Hogan <james.hogan@imgtec.com>
Tested-by: YunQiang Su <wzssyqa@gmail.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Jin Guojie <jinguojie@loongson.cn>
Message-Id: <1483592275-4496-5-git-send-email-jinguojie@loongson.cn>
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@jinguojie-loongson @rth7680
jinguojie-loongson authored and rth7680 committed Jan 6, 2017
1 parent 0119b19 commit 7f54eaa
Showing 1 changed file with 99 additions and 3 deletions.
102 changes: 99 additions & 3 deletions tcg/mips/tcg-target.inc.c
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Expand Up @@ -125,6 +125,8 @@ static const TCGReg tcg_target_call_oarg_regs[2] = {

static tcg_insn_unit *tb_ret_addr;
static tcg_insn_unit *bswap32_addr;
static tcg_insn_unit *bswap32u_addr;
static tcg_insn_unit *bswap64_addr;

static inline uint32_t reloc_pc16_val(tcg_insn_unit *pc, tcg_insn_unit *target)
{
Expand Down Expand Up @@ -622,7 +624,10 @@ static void tcg_out_bswap32u(TCGContext *s, TCGReg ret, TCGReg arg)
tcg_out_opc_reg(s, OPC_DSHD, ret, 0, ret);
tcg_out_dsrl(s, ret, ret, 32);
} else {
abort();
tcg_out_bswap_subr(s, bswap32u_addr);
/* delay slot -- never omit the insn, like tcg_out_mov might. */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP0, arg, TCG_REG_ZERO);
tcg_out_mov(s, TCG_TYPE_I32, ret, TCG_TMP3);
}
}

Expand All @@ -632,7 +637,10 @@ static void tcg_out_bswap64(TCGContext *s, TCGReg ret, TCGReg arg)
tcg_out_opc_reg(s, OPC_DSBH, ret, 0, arg);
tcg_out_opc_reg(s, OPC_DSHD, ret, 0, ret);
} else {
abort();
tcg_out_bswap_subr(s, bswap64_addr);
/* delay slot -- never omit the insn, like tcg_out_mov might. */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP0, arg, TCG_REG_ZERO);
tcg_out_mov(s, TCG_TYPE_I32, ret, TCG_TMP3);
}
}

Expand Down Expand Up @@ -2279,7 +2287,7 @@ static void tcg_target_qemu_prologue(TCGContext *s)
return;
}

/* Bswap subroutine: Input in TCG_TMP0, output in TCG_TMP3;
/* Bswap subroutines: Input in TCG_TMP0, output in TCG_TMP3;
clobbers TCG_TMP1, TCG_TMP2. */

/*
Expand All @@ -2305,6 +2313,94 @@ static void tcg_target_qemu_prologue(TCGContext *s)
tcg_out_opc_reg(s, OPC_JR, 0, TCG_REG_RA, 0);
/* t3 = dcba -- delay slot */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);

if (TCG_TARGET_REG_BITS == 32) {
return;
}

/*
* bswap32u -- unsigned 32-bit swap. a0 = ....abcd.
*/
bswap32u_addr = align_code_ptr(s);
/* t1 = (0000)000d */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP1, TCG_TMP0, 0xff);
/* t3 = 000a */
tcg_out_opc_sa(s, OPC_SRL, TCG_TMP3, TCG_TMP0, 24);
/* t1 = (0000)d000 */
tcg_out_dsll(s, TCG_TMP1, TCG_TMP1, 24);
/* t2 = 00c0 */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP2, TCG_TMP0, 0xff00);
/* t3 = d00a */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);
/* t1 = 0abc */
tcg_out_opc_sa(s, OPC_SRL, TCG_TMP1, TCG_TMP0, 8);
/* t2 = 0c00 */
tcg_out_opc_sa(s, OPC_SLL, TCG_TMP2, TCG_TMP2, 8);
/* t1 = 00b0 */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP1, TCG_TMP1, 0xff00);
/* t3 = dc0a */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP2);
tcg_out_opc_reg(s, OPC_JR, 0, TCG_REG_RA, 0);
/* t3 = dcba -- delay slot */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);

/*
* bswap64 -- 64-bit swap. a0 = abcdefgh
*/
bswap64_addr = align_code_ptr(s);
/* t3 = h0000000 */
tcg_out_dsll(s, TCG_TMP3, TCG_TMP0, 56);
/* t1 = 0000000a */
tcg_out_dsrl(s, TCG_TMP1, TCG_TMP0, 56);

/* t2 = 000000g0 */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP2, TCG_TMP0, 0xff00);
/* t3 = h000000a */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);
/* t1 = 00000abc */
tcg_out_dsrl(s, TCG_TMP1, TCG_TMP0, 40);
/* t2 = 0g000000 */
tcg_out_dsll(s, TCG_TMP2, TCG_TMP2, 40);
/* t1 = 000000b0 */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP1, TCG_TMP1, 0xff00);

/* t3 = hg00000a */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP2);
/* t2 = 0000abcd */
tcg_out_dsrl(s, TCG_TMP2, TCG_TMP0, 32);
/* t3 = hg0000ba */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);

/* t1 = 000000c0 */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP1, TCG_TMP2, 0xff00);
/* t2 = 0000000d */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP2, TCG_TMP2, 0x00ff);
/* t1 = 00000c00 */
tcg_out_dsll(s, TCG_TMP1, TCG_TMP1, 8);
/* t2 = 0000d000 */
tcg_out_dsll(s, TCG_TMP2, TCG_TMP2, 24);

/* t3 = hg000cba */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);
/* t1 = 00abcdef */
tcg_out_dsrl(s, TCG_TMP1, TCG_TMP0, 16);
/* t3 = hg00dcba */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP2);

/* t2 = 0000000f */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP2, TCG_TMP1, 0x00ff);
/* t1 = 000000e0 */
tcg_out_opc_imm(s, OPC_ANDI, TCG_TMP1, TCG_TMP1, 0xff00);
/* t2 = 00f00000 */
tcg_out_dsll(s, TCG_TMP2, TCG_TMP2, 40);
/* t1 = 000e0000 */
tcg_out_dsll(s, TCG_TMP1, TCG_TMP1, 24);

/* t3 = hgf0dcba */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP2);
tcg_out_opc_reg(s, OPC_JR, 0, TCG_REG_RA, 0);
/* t3 = hgfedcba -- delay slot */
tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);
}

static void tcg_target_init(TCGContext *s)
Expand Down

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