[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [4715] Emit trampolines manually in prologue
From: |
Fabrice Bellard |
Subject: |
Re: [Qemu-devel] [4715] Emit trampolines manually in prologue |
Date: |
Mon, 09 Jun 2008 22:24:40 +0200 |
User-agent: |
Thunderbird 1.5.0.9 (X11/20070212) |
This code is too complicated. Please remove it and just call an helper
to do the division if you really need it. The division is a slow
operation so no optimization is needed at this point.
Moreover, as I said previously there is no point in implementing divu[2]
as no QEMU target directly needs it.
Fabrice.
malc wrote:
> Revision: 4715
> http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=4715
> Author: malc
> Date: 2008-06-09 19:57:36 +0000 (Mon, 09 Jun 2008)
>
> Log Message:
> -----------
> Emit trampolines manually in prologue
>
> Modified Paths:
> --------------
> trunk/tcg/ppc/tcg-target.c
>
> Modified: trunk/tcg/ppc/tcg-target.c
> ===================================================================
> --- trunk/tcg/ppc/tcg-target.c 2008-06-09 19:57:27 UTC (rev 4714)
> +++ trunk/tcg/ppc/tcg-target.c 2008-06-09 19:57:36 UTC (rev 4715)
> @@ -23,6 +23,8 @@
> */
>
> static uint8_t *tb_ret_addr;
> +static uint8_t *udiv_addr;
> +static uint8_t *div_addr;
>
> #define FAST_PATH
> #if TARGET_PHYS_ADDR_BITS <= 32
> @@ -118,7 +120,7 @@
> };
>
> static const int tcg_target_callee_save_regs[] = {
> - TCG_REG_R13, /* sould r13 be saved? */
> + TCG_REG_R13, /* should r13 be saved? */
> TCG_REG_R14,
> TCG_REG_R15,
> TCG_REG_R16,
> @@ -135,6 +137,22 @@
> TCG_REG_R31
> };
>
> +static const int div_save_regs[] = {
> + TCG_REG_R4,
> + TCG_REG_R5,
> + TCG_REG_R7,
> + TCG_REG_R8,
> + TCG_REG_R9,
> + TCG_REG_R10,
> + TCG_REG_R11,
> + TCG_REG_R12,
> + TCG_REG_R13, /* should r13 be saved? */
> + TCG_REG_R24,
> + TCG_REG_R25,
> + TCG_REG_R26,
> + TCG_REG_R27,
> +};
> +
> static uint32_t reloc_pc24_val (void *pc, tcg_target_long target)
> {
> tcg_target_long disp;
> @@ -799,9 +817,25 @@
> #endif
> }
>
> +static uint64_t ppc_udiv_helper (uint64_t a, uint32_t b)
> +{
> + uint64_t rem, quo;
> + quo = a / b;
> + rem = a % b;
> + return (rem << 32) | (uint32_t) quo;
> +}
> +
> +static uint64_t ppc_div_helper (int64_t a, int32_t b)
> +{
> + int64_t rem, quo;
> + quo = a / b;
> + rem = a % b;
> + return (rem << 32) | (uint32_t) quo;
> +}
> +
> void tcg_target_qemu_prologue (TCGContext *s)
> {
> - int i, frame_size;
> + int i, j, frame_size;
>
> frame_size = 0
> + 4 /* back chain */
> @@ -837,6 +871,49 @@
> tcg_out32 (s, MTSPR | RS (0) | LR);
> tcg_out32 (s, ADDI | RT (1) | RA (1) | frame_size);
> tcg_out32 (s, BCLR | BO_ALWAYS);
> +
> + /* div trampolines */
> + for (j = 0; j < 2; ++j) {
> + tcg_target_long target;
> +
> + frame_size = 8 + ARRAY_SIZE (div_save_regs) * 4;
> + frame_size = (frame_size + 15) & ~15;
> +
> + if (j == 0) {
> + target = (tcg_target_long) ppc_udiv_helper;
> + udiv_addr = s->code_ptr;
> + }
> + else {
> + target = (tcg_target_long) ppc_div_helper;
> + div_addr = s->code_ptr;
> + }
> +
> + tcg_out32 (s, MFSPR | RT (0) | LR);
> + tcg_out32 (s, STWU | RS (1) | RA (1) | (-frame_size & 0xffff));
> + for (i = 0; i < ARRAY_SIZE (div_save_regs); ++i)
> + tcg_out32 (s, (STW
> + | RS (div_save_regs[i])
> + | RA (1)
> + | (i * 4 + 8)
> + )
> + );
> + tcg_out32 (s, STW | RS (0) | RA (1) | (frame_size - 4));
> + tcg_out_mov (s, 4, 6);
> + tcg_out_b (s, LK, target);
> + tcg_out_mov (s, 6, 4);
> +
> + for (i = 0; i < ARRAY_SIZE (div_save_regs); ++i)
> + tcg_out32 (s, (LWZ
> + | RT (div_save_regs[i])
> + | RA (1)
> + | (i * 4 + 8)
> + )
> + );
> + tcg_out32 (s, LWZ | RT (0) | RA (1) | (frame_size - 4));
> + tcg_out32 (s, MTSPR | RS (0) | LR);
> + tcg_out32 (s, ADDI | RT (1) | RA (1) | frame_size);
> + tcg_out32 (s, BCLR | BO_ALWAYS);
> + }
> }
>
> static void tcg_out_ld (TCGContext *s, TCGType type, int ret, int arg1,
> @@ -1018,41 +1095,6 @@
> tcg_out_label(s, label_next, (tcg_target_long)s->code_ptr);
> }
>
> -static uint64_t __attribute ((used)) ppc_udiv_helper (uint64_t a, uint32_t b)
> -{
> - uint64_t rem, quo;
> - quo = a / b;
> - rem = a % b;
> - return (rem << 32) | (uint32_t) quo;
> -}
> -
> -static uint64_t __attribute ((used)) ppc_div_helper (int64_t a, int32_t b)
> -{
> - int64_t rem, quo;
> - quo = a / b;
> - rem = a % b;
> - return (rem << 32) | (uint32_t) quo;
> -}
> -
> -#define MAKE_TRAMPOLINE(name) \
> -extern void name##_trampoline (void); \
> -asm (#name "_trampoline:\n" \
> - " mflr 0\n" \
> - " addi 1,1,-112\n" \
> - " mr 4,6\n" \
> - " stmw 7,0(1)\n" \
> - " stw 0,108(0)\n" \
> - " bl ppc_" #name "_helper\n" \
> - " lmw 7,0(1)\n" \
> - " lwz 0,108(0)\n" \
> - " addi 1,1,112\n" \
> - " mtlr 0\n" \
> - " blr\n" \
> - )
> -
> -MAKE_TRAMPOLINE (div);
> -MAKE_TRAMPOLINE (udiv);
> -
> static void tcg_out_div2 (TCGContext *s, int uns)
> {
> void *label1_ptr, *label2_ptr;
> @@ -1067,7 +1109,7 @@
> label1_ptr = s->code_ptr;
> tcg_out32 (s, BC | BI (7, CR_EQ) | BO_COND_TRUE);
>
> - tcg_out_b (s, LK, (tcg_target_long) (uns ? udiv_trampoline :
> div_trampoline));
> + tcg_out_b (s, LK, (tcg_target_long) (uns ? udiv_addr : div_addr));
>
> label2_ptr = s->code_ptr;
> tcg_out32 (s, B);
>
>
>
>
>