Hexagon (target/hexagon/arch.[ch]) utility functions

Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <1612763186-18161-16-git-send-email-tsimpson@quicinc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 300 insertions, 0 deletions

diff --git a/target/hexagon/arch.c b/target/hexagon/arch.c
new file mode 100644
index 0000000000..09de124818
--- /dev/null
+++ b/target/hexagon/arch.c
@@ -0,0 +1,300 @@
+/*
+ *  Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "fpu/softfloat.h"
+#include "cpu.h"
+#include "fma_emu.h"
+#include "arch.h"
+#include "macros.h"
+
+#define SF_BIAS        127
+#define SF_MAXEXP      254
+#define SF_MANTBITS    23
+#define float32_nan    make_float32(0xffffffff)
+
+#define BITS_MASK_8 0x5555555555555555ULL
+#define PAIR_MASK_8 0x3333333333333333ULL
+#define NYBL_MASK_8 0x0f0f0f0f0f0f0f0fULL
+#define BYTE_MASK_8 0x00ff00ff00ff00ffULL
+#define HALF_MASK_8 0x0000ffff0000ffffULL
+#define WORD_MASK_8 0x00000000ffffffffULL
+
+uint64_t interleave(uint32_t odd, uint32_t even)
+{
+    /* Convert to long long */
+    uint64_t myodd = odd;
+    uint64_t myeven = even;
+    /* First, spread bits out */
+    myodd = (myodd | (myodd << 16)) & HALF_MASK_8;
+    myeven = (myeven | (myeven << 16)) & HALF_MASK_8;
+    myodd = (myodd | (myodd << 8)) & BYTE_MASK_8;
+    myeven = (myeven | (myeven << 8)) & BYTE_MASK_8;
+    myodd = (myodd | (myodd << 4)) & NYBL_MASK_8;
+    myeven = (myeven | (myeven << 4)) & NYBL_MASK_8;
+    myodd = (myodd | (myodd << 2)) & PAIR_MASK_8;
+    myeven = (myeven | (myeven << 2)) & PAIR_MASK_8;
+    myodd = (myodd | (myodd << 1)) & BITS_MASK_8;
+    myeven = (myeven | (myeven << 1)) & BITS_MASK_8;
+    /* Now OR together */
+    return myeven | (myodd << 1);
+}
+
+uint64_t deinterleave(uint64_t src)
+{
+    /* Get odd and even bits */
+    uint64_t myodd = ((src >> 1) & BITS_MASK_8);
+    uint64_t myeven = (src & BITS_MASK_8);
+
+    /* Unspread bits */
+    myeven = (myeven | (myeven >> 1)) & PAIR_MASK_8;
+    myodd = (myodd | (myodd >> 1)) & PAIR_MASK_8;
+    myeven = (myeven | (myeven >> 2)) & NYBL_MASK_8;
+    myodd = (myodd | (myodd >> 2)) & NYBL_MASK_8;
+    myeven = (myeven | (myeven >> 4)) & BYTE_MASK_8;
+    myodd = (myodd | (myodd >> 4)) & BYTE_MASK_8;
+    myeven = (myeven | (myeven >> 8)) & HALF_MASK_8;
+    myodd = (myodd | (myodd >> 8)) & HALF_MASK_8;
+    myeven = (myeven | (myeven >> 16)) & WORD_MASK_8;
+    myodd = (myodd | (myodd >> 16)) & WORD_MASK_8;
+
+    /* Return odd bits in upper half */
+    return myeven | (myodd << 32);
+}
+
+uint32_t carry_from_add64(uint64_t a, uint64_t b, uint32_t c)
+{
+    uint64_t tmpa, tmpb, tmpc;
+    tmpa = fGETUWORD(0, a);
+    tmpb = fGETUWORD(0, b);
+    tmpc = tmpa + tmpb + c;
+    tmpa = fGETUWORD(1, a);
+    tmpb = fGETUWORD(1, b);
+    tmpc = tmpa + tmpb + fGETUWORD(1, tmpc);
+    tmpc = fGETUWORD(1, tmpc);
+    return tmpc;
+}
+
+int32_t conv_round(int32_t a, int n)
+{
+    int64_t val;
+
+    if (n == 0) {
+        val = a;
+    } else if ((a & ((1 << (n - 1)) - 1)) == 0) {    /* N-1..0 all zero? */
+        /* Add LSB from int part */
+        val = ((fSE32_64(a)) + (int64_t) (((uint32_t) ((1 << n) & a)) >> 1));
+    } else {
+        val = ((fSE32_64(a)) + (1 << (n - 1)));
+    }
+
+    val = val >> n;
+    return (int32_t)val;
+}
+
+/* Floating Point Stuff */
+
+static const int softfloat_roundingmodes[] = {
+    float_round_nearest_even,
+    float_round_to_zero,
+    float_round_down,
+    float_round_up,
+};
+
+void arch_fpop_start(CPUHexagonState *env)
+{
+    set_float_exception_flags(0, &env->fp_status);
+    set_float_rounding_mode(
+        softfloat_roundingmodes[fREAD_REG_FIELD(USR, USR_FPRND)],
+        &env->fp_status);
+}
+
+#ifdef CONFIG_USER_ONLY
+/*
+ * Hexagon Linux kernel only sets the relevant bits in USR (user status
+ * register).  The exception isn't raised to user mode, so we don't
+ * model it in qemu user mode.
+ */
+#define RAISE_FP_EXCEPTION   do {} while (0)
+#endif
+
+#define SOFTFLOAT_TEST_FLAG(FLAG, MYF, MYE) \
+    do { \
+        if (flags & FLAG) { \
+            if (GET_USR_FIELD(USR_##MYF) == 0) { \
+                SET_USR_FIELD(USR_##MYF, 1); \
+                if (GET_USR_FIELD(USR_##MYE)) { \
+                    RAISE_FP_EXCEPTION; \
+                } \
+            } \
+        } \
+    } while (0)
+
+void arch_fpop_end(CPUHexagonState *env)
+{
+    int flags = get_float_exception_flags(&env->fp_status);
+    if (flags != 0) {
+        SOFTFLOAT_TEST_FLAG(float_flag_inexact, FPINPF, FPINPE);
+        SOFTFLOAT_TEST_FLAG(float_flag_divbyzero, FPDBZF, FPDBZE);
+        SOFTFLOAT_TEST_FLAG(float_flag_invalid, FPINVF, FPINVE);
+        SOFTFLOAT_TEST_FLAG(float_flag_overflow, FPOVFF, FPOVFE);
+        SOFTFLOAT_TEST_FLAG(float_flag_underflow, FPUNFF, FPUNFE);
+    }
+}
+
+static float32 float32_mul_pow2(float32 a, uint32_t p, float_status *fp_status)
+{
+    float32 b = make_float32((SF_BIAS + p) << SF_MANTBITS);
+    return float32_mul(a, b, fp_status);
+}
+
+int arch_sf_recip_common(float32 *Rs, float32 *Rt, float32 *Rd, int *adjust,
+                         float_status *fp_status)
+{
+    int n_exp;
+    int d_exp;
+    int ret = 0;
+    float32 RsV, RtV, RdV;
+    int PeV = 0;
+    RsV = *Rs;
+    RtV = *Rt;
+    if (float32_is_any_nan(RsV) && float32_is_any_nan(RtV)) {
+        if (extract32(RsV & RtV, 22, 1) == 0) {
+            float_raise(float_flag_invalid, fp_status);
+        }
+        RdV = RsV = RtV = float32_nan;
+    } else if (float32_is_any_nan(RsV)) {
+        if (extract32(RsV, 22, 1) == 0) {
+            float_raise(float_flag_invalid, fp_status);
+        }
+        RdV = RsV = RtV = float32_nan;
+    } else if (float32_is_any_nan(RtV)) {
+        /* or put NaN in num/den fixup? */
+        if (extract32(RtV, 22, 1) == 0) {
+            float_raise(float_flag_invalid, fp_status);
+        }
+        RdV = RsV = RtV = float32_nan;
+    } else if (float32_is_infinity(RsV) && float32_is_infinity(RtV)) {
+        /* or put Inf in num fixup? */
+        RdV = RsV = RtV = float32_nan;
+        float_raise(float_flag_invalid, fp_status);
+    } else if (float32_is_zero(RsV) && float32_is_zero(RtV)) {
+        /* or put zero in num fixup? */
+        RdV = RsV = RtV = float32_nan;
+        float_raise(float_flag_invalid, fp_status);
+    } else if (float32_is_zero(RtV)) {
+        /* or put Inf in num fixup? */
+        uint8_t RsV_sign = float32_is_neg(RsV);
+        uint8_t RtV_sign = float32_is_neg(RtV);
+        RsV = infinite_float32(RsV_sign ^ RtV_sign);
+        RtV = float32_one;
+        RdV = float32_one;
+        if (float32_is_infinity(RsV)) {
+            float_raise(float_flag_divbyzero, fp_status);
+        }
+    } else if (float32_is_infinity(RtV)) {
+        RsV = make_float32(0x80000000 & (RsV ^ RtV));
+        RtV = float32_one;
+        RdV = float32_one;
+    } else if (float32_is_zero(RsV)) {
+        /* Does this just work itself out? */
+        /* No, 0/Inf causes problems. */
+        RsV = make_float32(0x80000000 & (RsV ^ RtV));
+        RtV = float32_one;
+        RdV = float32_one;
+    } else if (float32_is_infinity(RsV)) {
+        uint8_t RsV_sign = float32_is_neg(RsV);
+        uint8_t RtV_sign = float32_is_neg(RtV);
+        RsV = infinite_float32(RsV_sign ^ RtV_sign);
+        RtV = float32_one;
+        RdV = float32_one;
+    } else {
+        PeV = 0x00;
+        /* Basic checks passed */
+        n_exp = float32_getexp(RsV);
+        d_exp = float32_getexp(RtV);
+        if ((n_exp - d_exp + SF_BIAS) <= SF_MANTBITS) {
+            /* Near quotient underflow / inexact Q */
+            PeV = 0x80;
+            RtV = float32_mul_pow2(RtV, -64, fp_status);
+            RsV = float32_mul_pow2(RsV, 64, fp_status);
+        } else if ((n_exp - d_exp + SF_BIAS) > (SF_MAXEXP - 24)) {
+            /* Near quotient overflow */
+            PeV = 0x40;
+            RtV = float32_mul_pow2(RtV, 32, fp_status);
+            RsV = float32_mul_pow2(RsV, -32, fp_status);
+        } else if (n_exp <= SF_MANTBITS + 2) {
+            RtV = float32_mul_pow2(RtV, 64, fp_status);
+            RsV = float32_mul_pow2(RsV, 64, fp_status);
+        } else if (d_exp <= 1) {
+            RtV = float32_mul_pow2(RtV, 32, fp_status);
+            RsV = float32_mul_pow2(RsV, 32, fp_status);
+        } else if (d_exp > 252) {
+            RtV = float32_mul_pow2(RtV, -32, fp_status);
+            RsV = float32_mul_pow2(RsV, -32, fp_status);
+        }
+        RdV = 0;
+        ret = 1;
+    }
+    *Rs = RsV;
+    *Rt = RtV;
+    *Rd = RdV;
+    *adjust = PeV;
+    return ret;
+}
+
+int arch_sf_invsqrt_common(float32 *Rs, float32 *Rd, int *adjust,
+                           float_status *fp_status)
+{
+    float32 RsV, RdV;
+    int PeV = 0;
+    int r_exp;
+    int ret = 0;
+    RsV = *Rs;
+    if (float32_is_infinity(RsV)) {
+        if (extract32(RsV, 22, 1) == 0) {
+            float_raise(float_flag_invalid, fp_status);
+        }
+        RdV = RsV = float32_nan;
+    } else if (float32_lt(RsV, float32_zero, fp_status)) {
+        /* Negative nonzero values are NaN */
+        float_raise(float_flag_invalid, fp_status);
+        RsV = float32_nan;
+        RdV = float32_nan;
+    } else if (float32_is_infinity(RsV)) {
+        /* or put Inf in num fixup? */
+        RsV = infinite_float32(1);
+        RdV = infinite_float32(1);
+    } else if (float32_is_zero(RsV)) {
+        /* or put zero in num fixup? */
+        RdV = float32_one;
+    } else {
+        PeV = 0x00;
+        /* Basic checks passed */
+        r_exp = float32_getexp(RsV);
+        if (r_exp <= 24) {
+            RsV = float32_mul_pow2(RsV, 64, fp_status);
+            PeV = 0xe0;
+        }
+        RdV = 0;
+        ret = 1;
+    }
+    *Rs = RsV;
+    *Rd = RdV;
+    *adjust = PeV;
+    return ret;
+}