target-arm: Use new deposit and extract ops (59a71b4c) · Commits · SUMMER2020 / students / proj-2021291

target/arm/translate-a64.c

+29 −52

Original line number	Diff line number	Diff line
		@@ -3216,67 +3216,44 @@ static void disas_bitfield(DisasContext *s, uint32_t insn)
		low 32-bits anyway. */
		tcg_tmp = read_cpu_reg(s, rn, 1);

		/* Recognize the common aliases. */
		if (opc == 0) { /* SBFM */
		if (ri == 0) {
		if (si == 7) { /* SXTB */
		tcg_gen_ext8s_i64(tcg_rd, tcg_tmp);
		goto done;
		} else if (si == 15) { /* SXTH */
		tcg_gen_ext16s_i64(tcg_rd, tcg_tmp);
		goto done;
		} else if (si == 31) { /* SXTW */
		tcg_gen_ext32s_i64(tcg_rd, tcg_tmp);
		goto done;
		}
		}
		if (si == 63 \|\| (si == 31 && ri <= si)) { /* ASR */
		if (si == 31) {
		tcg_gen_ext32s_i64(tcg_tmp, tcg_tmp);
		}
		tcg_gen_sari_i64(tcg_rd, tcg_tmp, ri);
		/* Recognize simple(r) extractions. */
		if (si <= ri) {
		/* Wd<s-r:0> = Wn<s:r> */
		len = (si - ri) + 1;
		if (opc == 0) { /* SBFM: ASR, SBFX, SXTB, SXTH, SXTW */
		tcg_gen_sextract_i64(tcg_rd, tcg_tmp, ri, len);
		goto done;
		}
		} else if (opc == 2) { /* UBFM */
		if (ri == 0) { /* UXTB, UXTH, plus non-canonical AND */
		tcg_gen_andi_i64(tcg_rd, tcg_tmp, bitmask64(si + 1));
		} else if (opc == 2) { /* UBFM: UBFX, LSR, UXTB, UXTH */
		tcg_gen_extract_i64(tcg_rd, tcg_tmp, ri, len);
		return;
		}
		if (si == 63 \|\| (si == 31 && ri <= si)) { /* LSR */
		if (si == 31) {
		tcg_gen_ext32u_i64(tcg_tmp, tcg_tmp);
		}
		tcg_gen_shri_i64(tcg_rd, tcg_tmp, ri);
		return;
		}
		if (si + 1 == ri && si != bitsize - 1) { /* LSL */
		int shift = bitsize - 1 - si;
		tcg_gen_shli_i64(tcg_rd, tcg_tmp, shift);
		goto done;
		}
		}

		if (opc != 1) { /* SBFM or UBFM */
		tcg_gen_movi_i64(tcg_rd, 0);
		}

		/* do the bit move operation */
		if (si >= ri) {
		/* Wd<s-r:0> = Wn<s:r> */
		tcg_gen_shri_i64(tcg_tmp, tcg_tmp, ri);
		/* opc == 1, BXFIL fall through to deposit */
		tcg_gen_extract_i64(tcg_tmp, tcg_tmp, ri, len);
		pos = 0;
		len = (si - ri) + 1;
		} else {
		/* Wd<32+s-r,32-r> = Wn<s:0> */
		pos = bitsize - ri;
		/* Handle the ri > si case with a deposit
		* Wd<32+s-r,32-r> = Wn<s:0>
		*/
		len = si + 1;
		pos = (bitsize - ri) & (bitsize - 1);
		}

		tcg_gen_deposit_i64(tcg_rd, tcg_rd, tcg_tmp, pos, len);
		if (opc == 0 && len < ri) {
		/* SBFM: sign extend the destination field from len to fill
		the balance of the word. Let the deposit below insert all
		of those sign bits. */
		tcg_gen_sextract_i64(tcg_tmp, tcg_tmp, 0, len);
		len = ri;
		}

		if (opc == 0) { /* SBFM - sign extend the destination field */
		tcg_gen_shli_i64(tcg_rd, tcg_rd, 64 - (pos + len));
		tcg_gen_sari_i64(tcg_rd, tcg_rd, 64 - (pos + len));
		if (opc == 1) { /* BFM, BXFIL */
		tcg_gen_deposit_i64(tcg_rd, tcg_rd, tcg_tmp, pos, len);
		} else {
		/* SBFM or UBFM: We start with zero, and we haven't modified
		any bits outside bitsize, therefore the zero-extension
		below is unneeded. */
		tcg_gen_deposit_z_i64(tcg_rd, tcg_tmp, pos, len);
		return;
		}

		done:

target/arm/translate.c

+8 −29

Original line number	Diff line number	Diff line
		@@ -288,29 +288,6 @@ static void gen_revsh(TCGv_i32 var)
		tcg_gen_ext16s_i32(var, var);
		}

		/* Unsigned bitfield extract. */
		static void gen_ubfx(TCGv_i32 var, int shift, uint32_t mask)
		{
		if (shift)
		tcg_gen_shri_i32(var, var, shift);
		tcg_gen_andi_i32(var, var, mask);
		}

		/* Signed bitfield extract. */
		static void gen_sbfx(TCGv_i32 var, int shift, int width)
		{
		uint32_t signbit;

		if (shift)
		tcg_gen_sari_i32(var, var, shift);
		if (shift + width < 32) {
		signbit = 1u << (width - 1);
		tcg_gen_andi_i32(var, var, (1u << width) - 1);
		tcg_gen_xori_i32(var, var, signbit);
		tcg_gen_subi_i32(var, var, signbit);
		}
		}

		/* Return (b << 32) + a. Mark inputs as dead */
		static TCGv_i64 gen_addq_msw(TCGv_i64 a, TCGv_i32 b)
		{
		@@ -9178,9 +9155,9 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn)
		goto illegal_op;
		if (i < 32) {
		if (op1 & 0x20) {
		gen_ubfx(tmp, shift, (1u << i) - 1);
		tcg_gen_extract_i32(tmp, tmp, shift, i);
		} else {
		gen_sbfx(tmp, shift, i);
		tcg_gen_sextract_i32(tmp, tmp, shift, i);
		}
		}
		store_reg(s, rd, tmp);
		@@ -10497,15 +10474,17 @@ static int disas_thumb2_insn(CPUARMState env, DisasContext s, uint16_t insn_hw
		imm++;
		if (shift + imm > 32)
		goto illegal_op;
		if (imm < 32)
		gen_sbfx(tmp, shift, imm);
		if (imm < 32) {
		tcg_gen_sextract_i32(tmp, tmp, shift, imm);
		}
		break;
		case 6: /* Unsigned bitfield extract. */
		imm++;
		if (shift + imm > 32)
		goto illegal_op;
		if (imm < 32)
		gen_ubfx(tmp, shift, (1u << imm) - 1);
		if (imm < 32) {
		tcg_gen_extract_i32(tmp, tmp, shift, imm);
		}
		break;
		case 3: /* Bitfield insert/clear. */
		if (imm < shift)