ARM: Math inlines
Xerxes Rånby
xerxes at zafena.se
Wed Feb 22 07:16:13 PST 2012
2012-01-24 15:32, Andrew Haley skrev:
> This is a bit of "low-hanging fruit".
>
> Modern ARMs have instructions for things like sqrt, so it doesn't make
> any sense to call native methods for such things. This patch handles
> all of the java.lang.Math special method types, calling the StrictMath
> JNI functions for everything we can't inline. For trunk only.
>
> Andrew.
I have done some cross cheking and since the VSQRT are available on both Cortex-A8, A9 and later i consider it safe to enable it for all __ARM_PCS_VFP builds.
Also its nice that the VFP instructions follow IEEE754 standards so this should not introduce any rounding issues compared to the interpreted version.
Please push to IcedTea6 HEAD
Cheers
Xerxes
>
>
> 2012-01-24 Andrew Haley <aph at redhat.com>
>
> * arm_port/hotspot/src/cpu/zero/vm/thumb2.cpp ()
> (handle_special_method, jstack_to_vfp, vfp_to_jstack): New
> functions.
> (Thumb2_codegen): Call handle_special_method.
> (t_vop_ops): Add VSQRT.
> (T_VMOVD_VFP_TOVFP): New macro.
> (vmov_reg_d_VFP_to_VFP): New function.
>
> diff -r 8dd5206f92f1 arm_port/hotspot/src/cpu/zero/vm/thumb2.cpp
> --- a/arm_port/hotspot/src/cpu/zero/vm/thumb2.cpp Mon Jan 23 16:43:01 2012 +0000
> +++ b/arm_port/hotspot/src/cpu/zero/vm/thumb2.cpp Tue Jan 24 14:26:48 2012 +0000
> @@ -1555,7 +1555,7 @@
> } while (!(bc_stackinfo[bci] & BC_BRANCH_TARGET));
> return 0;
> }
> -#endif // ZOMBIT_DETECTION
> +#endif // ZOMBIE_DETECTION
>
> void Thumb2_RegAlloc(Thumb2_Info *jinfo)
> {
> @@ -1989,12 +1989,14 @@
> #define VP_SUB 1
> #define VP_MUL 2
> #define VP_DIV 3
> +#define VP_SQRT 4
>
> static const unsigned t_vop_ops[] = {
> 0xee300a00, // VADD
> 0xee300a40, // VSUB
> 0xee200a00, // VMUL
> 0xee800a00, // VDIV
> + 0xeeb10bc0 // VSQRT
> };
>
> #define VP_REG(op) t_vop_ops[op]
> @@ -2160,6 +2162,9 @@
> #define T_VMOVD_TOVFP(dst, src_lo, src_hi) \
> (0xec400b10 | ((src_lo) << 12) | ((src_hi) << 16) | (((dst) & 0x10)<<(5-4)) | ((dst) & 0x0f))
>
> +// VFP reg to VFP re move.
> +#define T_VMOVD_VFP_TOVFP(dst, src) (0xeeb00b40 | (((dst) & 0x0f) << 12) | ((src) & 0x0f))
> +
> #define T_VOP_REG_S(op, dst, lho, rho) ((op) | \
> (((dst) & 1) << 22) | (((dst) & 0x1e) << (12-1)) | \
> (((lho) & 1) << 7) | (((lho) & 0x1e) << (16-1)) | \
> @@ -2728,6 +2733,11 @@
> return out_16x2(codebuf, T_VMOVD_TOVFP(dst, src_lo, src_hi));
> }
>
> +int vmov_reg_d_VFP_to_VFP(CodeBuf *codebuf, u32 dst, u32 src)
> +{
> + return out_16x2(codebuf, T_VMOVD_VFP_TOVFP(dst, src));
> +}
> +
> int vmov_reg_d_toARM(CodeBuf *codebuf, u32 dst_lo, u32 dst_hi, u32 src)
> {
> return out_16x2(codebuf, T_VMOVD_TOARM(dst_lo, dst_hi, src));
> @@ -4967,6 +4977,128 @@
>
> extern "C" void _ZN18InterpreterRuntime18register_finalizerEP10JavaThreadP7oopDesc(void);
>
> +// Push VFP_REG to the java stack.
> +static void vfp_to_jstack(Thumb2_Info *jinfo, int vfp_reg) {
> + Thumb2_Stack *jstack = jinfo->jstack;
> + unsigned r_lo, r_hi;
> + r_hi = PUSH(jstack, JSTACK_REG(jstack));
> + r_lo = PUSH(jstack, JSTACK_REG(jstack));
> + vmov_reg_d_toARM(jinfo->codebuf, r_lo, r_hi, vfp_reg);
> +}
> +
> +// Pop the java stack to VFP_REG .
> +static void jstack_to_vfp(Thumb2_Info *jinfo, int vfp_reg) {
> + Thumb2_Stack *jstack = jinfo->jstack;
> + unsigned r_lo, r_hi;
> + Thumb2_Fill(jinfo, 2);
> + r_lo = POP(jstack);
> + r_hi = POP(jstack);
> + vmov_reg_d_toVFP(jinfo->codebuf, vfp_reg, r_lo, r_hi);
> + Thumb2_Flush(jinfo);
> +}
> +
> +// Expand a call to a "special" method. These are usually inlines of
> +// java.lang.Math methods. Return true if the inlining succeeded.
> +static bool handle_special_method(methodOop callee, Thumb2_Info *jinfo) {
> +#ifdef __ARM_PCS_VFP
> + Thumb2_Stack *jstack = jinfo->jstack;
> +
> + const char *entry_name;
> +
> + unsigned loc1 = 0;
> +
> + switch (Interpreter::method_kind(callee)) {
> + case Interpreter::java_lang_math_abs:
> + {
> + unsigned r_lo, r_hi;
> +
> + Thumb2_Fill(jinfo, 2);
> + r_lo = POP(jstack);
> + r_hi = POP(jstack);
> + dop_imm_s(jinfo->codebuf, DP_BIC, r_hi, r_hi, 0x80000000, 0);
> + PUSH(jstack, r_hi);
> + PUSH(jstack, r_lo);
> +
> + return true;
> + }
> +
> + case Interpreter::java_lang_math_sin:
> + entry_name = "Java_java_lang_StrictMath_sin";
> + break;
> +
> + case Interpreter::java_lang_math_cos:
> + entry_name = "Java_java_lang_StrictMath_cos";
> + break;
> +
> + case Interpreter::java_lang_math_tan:
> + entry_name = "Java_java_lang_StrictMath_tan";
> + break;
> +
> + case Interpreter::java_lang_math_sqrt:
> + {
> + void *entry_point = dlsym(NULL, "Java_java_lang_StrictMath_sqrt");
> + if (! entry_point)
> + return false;
> +
> + unsigned r_lo, r_hi, r_res_lo, r_res_hi;
> +
> + // Make sure that canonical NaNs are returned, as per the spec.
> + //
> + // Generate:
> + // vsqrt.f64 d0, d1
> + // vcmp.f64 d0, d0
> + // vmrs APSR_nzcv, fpscr
> + // beq.n 0f
> + // vmov.f64 d0, d1
> + // blx Java_java_lang_StrictMath_sqrt
> + // 0:
> + jstack_to_vfp(jinfo, VFP_D1);
> + vop_reg_d(jinfo->codebuf, VP_SQRT, VFP_D0, 0, VFP_D1);
> + vcmp_reg_d(jinfo->codebuf, VFP_D0, VFP_D0, 0);
> + vmrs(jinfo->codebuf, ARM_PC);
> + int loc = forward_16(jinfo->codebuf);
> + vmov_reg_d_VFP_to_VFP(jinfo->codebuf, VFP_D0, VFP_D1);
> + // FIXME: The JNI StrictMath routines don't use the JNIEnv *env
> + // parameter, so it's arguably pointless to pass it here.
> + add_imm(jinfo->codebuf, ARM_R0, Rthread, THREAD_JNI_ENVIRONMENT);
> + blx(jinfo->codebuf, (unsigned)entry_point);
> + bcc_patch(jinfo->codebuf, COND_EQ, loc);
> + vfp_to_jstack(jinfo, VFP_D0);
> +
> + return true;
> + }
> +
> + case Interpreter::java_lang_math_log:
> + entry_name = "Java_java_lang_StrictMath_log";
> + break;
> +
> + case Interpreter::java_lang_math_log10:
> + entry_name = "Java_java_lang_StrictMath_log10";
> + break;
> +
> + default:
> + return false;
> + }
> +
> + void *entry_point = dlsym(NULL, entry_name);
> + if (! entry_point)
> + return false;
> +
> + unsigned r_lo, r_hi, r_res_lo, r_res_hi;
> +
> + jstack_to_vfp(jinfo, VFP_D0);
> + // FIXME: The JNI StrictMath routines don't use the JNIEnv *env
> + // parameter, so it's arguably pointless to pass it here.
> + add_imm(jinfo->codebuf, ARM_R0, Rthread, THREAD_JNI_ENVIRONMENT);
> + blx(jinfo->codebuf, (unsigned)entry_point);
> + vfp_to_jstack(jinfo, VFP_D0);
> +
> + return true;
> +#else
> + return false;
> +#endif // __ARM_PCS_VFP
> +}
> +
> void Thumb2_codegen(Thumb2_Info *jinfo, unsigned start)
> {
> unsigned code_size = jinfo->code_size;
> @@ -6035,6 +6167,10 @@
> }
>
> callee = (methodOop)cache->f1();
> +
> + if (handle_special_method(callee, jinfo))
> + break;
> +
> if (callee->is_accessor()) {
> u1 *code = callee->code_base();
> int index = GET_NATIVE_U2(&code[2]);
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