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Re: [Qemu-devel] [PATCH 1/9] target-arm: A64: add support for stp (store
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH 1/9] target-arm: A64: add support for stp (store pair) |
Date: |
Mon, 09 Dec 2013 12:17:38 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 |
On 12/09/2013 10:12 AM, Peter Maydell wrote:
> +static void do_gpr_st(DisasContext *s, TCGv_i64 source,
> + TCGv_i64 tcg_addr, int size)
> +{
> + switch (size) {
> + case 0:
> + tcg_gen_qemu_st8(source, tcg_addr, get_mem_index(s));
> + break;
> + case 1:
> + tcg_gen_qemu_st16(source, tcg_addr, get_mem_index(s));
> + break;
> + case 2:
> + tcg_gen_qemu_st32(source, tcg_addr, get_mem_index(s));
> + break;
> + case 3:
> + tcg_gen_qemu_st64(source, tcg_addr, get_mem_index(s));
> + break;
Please use the new ldst entry points. In this case,
tcg_gen_qemu_st_i64(source, tcg_addr, get_mem_index(s), MO_TE + size)
since size is already log2.
> +static void do_fp_st(DisasContext *s, int srcidx, TCGv_i64 tcg_addr, int
> size)
> +{
> + /* This writes the bottom N bits of a 128 bit wide vector to memory */
> + int freg_offs = offsetof(CPUARMState, vfp.regs[srcidx * 2]);
> + TCGv_i64 tmp = tcg_temp_new_i64();
> +
> + switch (size) {
> + case 0:
> + tcg_gen_ld8u_i64(tmp, cpu_env, freg_offs);
> + tcg_gen_qemu_st8(tmp, tcg_addr, get_mem_index(s));
> + break;
> + case 1:
> + tcg_gen_ld16u_i64(tmp, cpu_env, freg_offs);
> + tcg_gen_qemu_st16(tmp, tcg_addr, get_mem_index(s));
> + break;
> + case 2:
> + tcg_gen_ld32u_i64(tmp, cpu_env, freg_offs);
> + tcg_gen_qemu_st32(tmp, tcg_addr, get_mem_index(s));
> + break;
> + case 3:
> + tcg_gen_ld_i64(tmp, cpu_env, freg_offs);
> + tcg_gen_qemu_st64(tmp, tcg_addr, get_mem_index(s));
> + break;
> + case 4:
> + {
> + TCGv_i64 tcg_hiaddr = tcg_temp_new_i64();
> + tcg_gen_ld_i64(tmp, cpu_env, freg_offs);
> + tcg_gen_qemu_st64(tmp, tcg_addr, get_mem_index(s));
> + tcg_gen_ld_i64(tmp, cpu_env, freg_offs + sizeof(float64));
> + tcg_gen_addi_i64(tcg_hiaddr, tcg_addr, 8);
> + tcg_gen_qemu_st64(tmp, tcg_hiaddr, get_mem_index(s));
> + tcg_temp_free_i64(tcg_hiaddr);
> + break;
> + }
You'll certainly have to continue to special-case the 128-bit store, but the
other sizes need not be.
> +/*
> + * C5.6.177 STP (Store Pair - non vector)
> + * C6.3.284 STP (Store Pair of SIMD&FP)
> + *
> + * 31 30 29 27 26 25 23 22 21 15 14 10 9 5 4 0
> + * +-----+-------+---+-------+--+-----------------------------+
> + * | opc | 1 0 1 | V | index | 0| imm7 | Rt2 | Rn | Rt |
> + * +-----+-------+---+-------+--+-------+-------+------+------+
> + *
> + * opc: STP 00 -> 32 bit, 10 -> 64 bit
> + * STP (SIMD&FP) 00 -> 32 bit, 01 -> 64 bit, 10 -> 128 bit
> + * idx: 001 -> post-index, 011 -> pre-index, 010 -> signed off
> + *
> + * Rt, Rt2 = GPR or SIMD registers to be stored
> + * Rn = general purpose register containing address
> + * imm7 = signed offset (multiple of 4 or 8 depending on size)
> + */
> +static void handle_stp(DisasContext *s, uint32_t insn)
> +{
> + int rt = extract32(insn, 0, 5);
> + int rn = extract32(insn, 5, 5);
> + int rt2 = extract32(insn, 10, 5);
> + int64_t offset = sextract32(insn, 15, 7);
> + int type = extract32(insn, 23, 2);
> + bool is_vector = extract32(insn, 26, 1);
> + int opc = extract32(insn, 30, 2);
> +
> + TCGv_i64 tcg_rt = cpu_reg(s, rt);
> + TCGv_i64 tcg_rt2 = cpu_reg(s, rt2);
If you're going to combine vector and non-vector STP, then I think it would be
cleaner if you didn't load these registers so early, when we're not even sure
if we're talking about general registers.
> + if (wback) {
> + if (postindex) {
> + tcg_gen_addi_i64(tcg_addr, tcg_addr, offset - (1 << size));
> + } else {
> + tcg_gen_subi_i64(tcg_addr, tcg_addr, 1 << size);
> + }
Perhaps better as
tcg_gen_addi_i64(tcg_addr, tcg_addr,
(postindex ? offset : 0) - (1 << size));
?
r~
- Re: [Qemu-devel] [PATCH 2/9] target-arm: A64: add support for ldp (load pair), (continued)
- [Qemu-devel] [PATCH 4/9] target-arm: A64: add support for ld/st with reg offset, Peter Maydell, 2013/12/09
- [Qemu-devel] [PATCH 8/9] target-arm: A64: add support for 3 src data proc insns, Peter Maydell, 2013/12/09
- [Qemu-devel] [PATCH 6/9] target-arm: A64: add support for add, addi, sub, subi, Peter Maydell, 2013/12/09
- [Qemu-devel] [PATCH 1/9] target-arm: A64: add support for stp (store pair), Peter Maydell, 2013/12/09
- Re: [Qemu-devel] [PATCH 1/9] target-arm: A64: add support for stp (store pair),
Richard Henderson <=
- [Qemu-devel] [PATCH 9/9] target-arm: A64: implement SVC, BRK, Peter Maydell, 2013/12/09
- Re: [Qemu-devel] [PATCH 0/9] target-arm: A64 decoder set 3: loads, stores, misc integer, Peter Maydell, 2013/12/09