target/mips: MXU: Add handlers for max/min instructions

Add translation handlers for six max/min MXU instructions.

Reviewed-by: Stefan Markovic <smarkovic@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>

1 files changed, 279 insertions, 21 deletions

diff --git a/target/mips/translate.c b/target/mips/translate.c
index a339f72..44142ea 100644
--- a/target/mips/translate.c
+++ b/target/mips/translate.c
@@ -24824,6 +24824,282 @@ static void gen_mxu_S32XOR(DisasContext *ctx)
 
 
 /*
+ *                   MXU instruction category max/min
+ *                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *                     S32MAX     D16MAX     Q8MAX
+ *                     S32MIN     D16MIN     Q8MIN
+ */
+
+/*
+ *  S32MAX XRa, XRb, XRc
+ *    Update XRa with the maximum of signed 32-bit integers contained
+ *    in XRb and XRc.
+ *
+ *  S32MIN XRa, XRb, XRc
+ *    Update XRa with the minimum of signed 32-bit integers contained
+ *    in XRb and XRc.
+ *
+ *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ *  +-----------+---------+-----+-------+-------+-------+-----------+
+ *  |  SPECIAL2 |0 0 0 0 0| opc |  XRc  |  XRb  |  XRa  |MXU__POOL00|
+ *  +-----------+---------+-----+-------+-------+-------+-----------+
+ */
+static void gen_mxu_S32MAX_S32MIN(DisasContext *ctx)
+{
+    uint32_t pad, opc, XRc, XRb, XRa;
+
+    pad = extract32(ctx->opcode, 21, 5);
+    opc = extract32(ctx->opcode, 18, 3);
+    XRc = extract32(ctx->opcode, 14, 4);
+    XRb = extract32(ctx->opcode, 10, 4);
+    XRa = extract32(ctx->opcode,  6, 4);
+
+    if (unlikely(pad != 0)) {
+        /* opcode padding incorrect -> do nothing */
+    } else if (unlikely(XRa == 0)) {
+        /* destination is zero register -> do nothing */
+    } else if (unlikely((XRb == 0) && (XRc == 0))) {
+        /* both operands zero registers -> just set destination to zero */
+        tcg_gen_movi_i32(mxu_gpr[XRa - 1], 0);
+    } else if (unlikely((XRb == 0) || (XRc == 0))) {
+        /* exactly one operand is zero register - find which one is not...*/
+        uint32_t XRx = XRb ? XRb : XRc;
+        /* ...and do max/min operation with one operand 0 */
+        if (opc == OPC_MXU_S32MAX) {
+            tcg_gen_smax_i32(mxu_gpr[XRa - 1], mxu_gpr[XRx - 1], 0);
+        } else {
+            tcg_gen_smin_i32(mxu_gpr[XRa - 1], mxu_gpr[XRx - 1], 0);
+        }
+    } else if (unlikely(XRb == XRc)) {
+        /* both operands same -> just set destination to one of them */
+        tcg_gen_mov_i32(mxu_gpr[XRa - 1], mxu_gpr[XRb - 1]);
+    } else {
+        /* the most general case */
+        if (opc == OPC_MXU_S32MAX) {
+            tcg_gen_smax_i32(mxu_gpr[XRa - 1], mxu_gpr[XRb - 1],
+                                               mxu_gpr[XRc - 1]);
+        } else {
+            tcg_gen_smin_i32(mxu_gpr[XRa - 1], mxu_gpr[XRb - 1],
+                                               mxu_gpr[XRc - 1]);
+        }
+    }
+}
+
+/*
+ *  D16MAX
+ *    Update XRa with the 16-bit-wise maximums of signed integers
+ *    contained in XRb and XRc.
+ *
+ *  D16MIN
+ *    Update XRa with the 16-bit-wise minimums of signed integers
+ *    contained in XRb and XRc.
+ *
+ *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ *  +-----------+---------+-----+-------+-------+-------+-----------+
+ *  |  SPECIAL2 |0 0 0 0 0| opc |  XRc  |  XRb  |  XRa  |MXU__POOL00|
+ *  +-----------+---------+-----+-------+-------+-------+-----------+
+ */
+static void gen_mxu_D16MAX_D16MIN(DisasContext *ctx)
+{
+    uint32_t pad, opc, XRc, XRb, XRa;
+
+    pad = extract32(ctx->opcode, 21, 5);
+    opc = extract32(ctx->opcode, 18, 3);
+    XRc = extract32(ctx->opcode, 14, 4);
+    XRb = extract32(ctx->opcode, 10, 4);
+    XRa = extract32(ctx->opcode,  6, 4);
+
+    if (unlikely(pad != 0)) {
+        /* opcode padding incorrect -> do nothing */
+    } else if (unlikely(XRc == 0)) {
+        /* destination is zero register -> do nothing */
+    } else if (unlikely((XRb == 0) && (XRa == 0))) {
+        /* both operands zero registers -> just set destination to zero */
+        tcg_gen_movi_i32(mxu_gpr[XRc - 1], 0);
+    } else if (unlikely((XRb == 0) || (XRa == 0))) {
+        /* exactly one operand is zero register - find which one is not...*/
+        uint32_t XRx = XRb ? XRb : XRc;
+        /* ...and do half-word-wise max/min with one operand 0 */
+        TCGv_i32 t0 = tcg_temp_new();
+        TCGv_i32 t1 = tcg_const_i32(0);
+
+        /* the left half-word first */
+        tcg_gen_andi_i32(t0, mxu_gpr[XRx - 1], 0xFFFF0000);
+        if (opc == OPC_MXU_D16MAX) {
+            tcg_gen_smax_i32(mxu_gpr[XRa - 1], t0, t1);
+        } else {
+            tcg_gen_smin_i32(mxu_gpr[XRa - 1], t0, t1);
+        }
+
+        /* the right half-word */
+        tcg_gen_andi_i32(t0, mxu_gpr[XRx - 1], 0x0000FFFF);
+        /* move half-words to the leftmost position */
+        tcg_gen_shli_i32(t0, t0, 16);
+        /* t0 will be max/min of t0 and t1 */
+        if (opc == OPC_MXU_D16MAX) {
+            tcg_gen_smax_i32(t0, t0, t1);
+        } else {
+            tcg_gen_smin_i32(t0, t0, t1);
+        }
+        /* return resulting half-words to its original position */
+        tcg_gen_shri_i32(t0, t0, 16);
+        /* finaly update the destination */
+        tcg_gen_or_i32(mxu_gpr[XRa - 1], mxu_gpr[XRa - 1], t0);
+
+        tcg_temp_free(t1);
+        tcg_temp_free(t0);
+    } else if (unlikely(XRb == XRc)) {
+        /* both operands same -> just set destination to one of them */
+        tcg_gen_mov_i32(mxu_gpr[XRa - 1], mxu_gpr[XRb - 1]);
+    } else {
+        /* the most general case */
+        TCGv_i32 t0 = tcg_temp_new();
+        TCGv_i32 t1 = tcg_temp_new();
+
+        /* the left half-word first */
+        tcg_gen_andi_i32(t0, mxu_gpr[XRb - 1], 0xFFFF0000);
+        tcg_gen_andi_i32(t1, mxu_gpr[XRc - 1], 0xFFFF0000);
+        if (opc == OPC_MXU_D16MAX) {
+            tcg_gen_smax_i32(mxu_gpr[XRa - 1], t0, t1);
+        } else {
+            tcg_gen_smin_i32(mxu_gpr[XRa - 1], t0, t1);
+        }
+
+        /* the right half-word */
+        tcg_gen_andi_i32(t0, mxu_gpr[XRb - 1], 0x0000FFFF);
+        tcg_gen_andi_i32(t1, mxu_gpr[XRc - 1], 0x0000FFFF);
+        /* move half-words to the leftmost position */
+        tcg_gen_shli_i32(t0, t0, 16);
+        tcg_gen_shli_i32(t1, t1, 16);
+        /* t0 will be max/min of t0 and t1 */
+        if (opc == OPC_MXU_D16MAX) {
+            tcg_gen_smax_i32(t0, t0, t1);
+        } else {
+            tcg_gen_smin_i32(t0, t0, t1);
+        }
+        /* return resulting half-words to its original position */
+        tcg_gen_shri_i32(t0, t0, 16);
+        /* finaly update the destination */
+        tcg_gen_or_i32(mxu_gpr[XRa - 1], mxu_gpr[XRa - 1], t0);
+
+        tcg_temp_free(t1);
+        tcg_temp_free(t0);
+    }
+}
+
+/*
+ *  Q8MAX
+ *    Update XRa with the 8-bit-wise maximums of signed integers
+ *    contained in XRb and XRc.
+ *
+ *  Q8MIN
+ *    Update XRa with the 8-bit-wise minimums of signed integers
+ *    contained in XRb and XRc.
+ *
+ *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ *  +-----------+---------+-----+-------+-------+-------+-----------+
+ *  |  SPECIAL2 |0 0 0 0 0| opc |  XRc  |  XRb  |  XRa  |MXU__POOL00|
+ *  +-----------+---------+-----+-------+-------+-------+-----------+
+ */
+static void gen_mxu_Q8MAX_Q8MIN(DisasContext *ctx)
+{
+    uint32_t pad, opc, XRc, XRb, XRa;
+
+    pad = extract32(ctx->opcode, 21, 5);
+    opc = extract32(ctx->opcode, 18, 3);
+    XRc = extract32(ctx->opcode, 14, 4);
+    XRb = extract32(ctx->opcode, 10, 4);
+    XRa = extract32(ctx->opcode,  6, 4);
+
+    if (unlikely(pad != 0)) {
+        /* opcode padding incorrect -> do nothing */
+    } else if (unlikely(XRa == 0)) {
+        /* destination is zero register -> do nothing */
+    } else if (unlikely((XRb == 0) && (XRc == 0))) {
+        /* both operands zero registers -> just set destination to zero */
+        tcg_gen_movi_i32(mxu_gpr[XRa - 1], 0);
+    } else if (unlikely((XRb == 0) || (XRc == 0))) {
+        /* exactly one operand is zero register - make it be the first...*/
+        uint32_t XRx = XRb ? XRb : XRc;
+        /* ...and do byte-wise max/min with one operand 0 */
+        TCGv_i32 t0 = tcg_temp_new();
+        TCGv_i32 t1 = tcg_const_i32(0);
+        int32_t i;
+
+        /* the leftmost byte (byte 3) first */
+        tcg_gen_andi_i32(t0, mxu_gpr[XRx - 1], 0xFF000000);
+        if (opc == OPC_MXU_Q8MAX) {
+            tcg_gen_smax_i32(mxu_gpr[XRa - 1], t0, t1);
+        } else {
+            tcg_gen_smin_i32(mxu_gpr[XRa - 1], t0, t1);
+        }
+
+        /* bytes 2, 1, 0 */
+        for (i = 2; i >= 0; i--) {
+            /* extract the byte */
+            tcg_gen_andi_i32(t0, mxu_gpr[XRx - 1], 0xFF << (8 * i));
+            /* move the byte to the leftmost position */
+            tcg_gen_shli_i32(t0, t0, 8 * (3 - i));
+            /* t0 will be max/min of t0 and t1 */
+            if (opc == OPC_MXU_Q8MAX) {
+                tcg_gen_smax_i32(t0, t0, t1);
+            } else {
+                tcg_gen_smin_i32(t0, t0, t1);
+            }
+            /* return resulting byte to its original position */
+            tcg_gen_shri_i32(t0, t0, 8 * (3 - i));
+            /* finaly update the destination */
+            tcg_gen_or_i32(mxu_gpr[XRa - 1], mxu_gpr[XRa - 1], t0);
+        }
+
+        tcg_temp_free(t1);
+        tcg_temp_free(t0);
+    } else if (unlikely(XRb == XRc)) {
+        /* both operands same -> just set destination to one of them */
+        tcg_gen_mov_i32(mxu_gpr[XRa - 1], mxu_gpr[XRb - 1]);
+    } else {
+        /* the most general case */
+        TCGv_i32 t0 = tcg_temp_new();
+        TCGv_i32 t1 = tcg_temp_new();
+        int32_t i;
+
+        /* the leftmost bytes (bytes 3) first */
+        tcg_gen_andi_i32(t0, mxu_gpr[XRb - 1], 0xFF000000);
+        tcg_gen_andi_i32(t1, mxu_gpr[XRc - 1], 0xFF000000);
+        if (opc == OPC_MXU_Q8MAX) {
+            tcg_gen_smax_i32(mxu_gpr[XRa - 1], t0, t1);
+        } else {
+            tcg_gen_smin_i32(mxu_gpr[XRa - 1], t0, t1);
+        }
+
+        /* bytes 2, 1, 0 */
+        for (i = 2; i >= 0; i--) {
+            /* extract corresponding bytes */
+            tcg_gen_andi_i32(t0, mxu_gpr[XRb - 1], 0xFF << (8 * i));
+            tcg_gen_andi_i32(t1, mxu_gpr[XRc - 1], 0xFF << (8 * i));
+            /* move the bytes to the leftmost position */
+            tcg_gen_shli_i32(t0, t0, 8 * (3 - i));
+            tcg_gen_shli_i32(t1, t1, 8 * (3 - i));
+            /* t0 will be max/min of t0 and t1 */
+            if (opc == OPC_MXU_Q8MAX) {
+                tcg_gen_smax_i32(t0, t0, t1);
+            } else {
+                tcg_gen_smin_i32(t0, t0, t1);
+            }
+            /* return resulting byte to its original position */
+            tcg_gen_shri_i32(t0, t0, 8 * (3 - i));
+            /* finaly update the destination */
+            tcg_gen_or_i32(mxu_gpr[XRa - 1], mxu_gpr[XRa - 1], t0);
+        }
+
+        tcg_temp_free(t1);
+        tcg_temp_free(t0);
+    }
+}
+
+
+/*
  * Decoding engine for MXU
  * =======================
  */
@@ -24844,34 +25120,16 @@ static void decode_opc_mxu__pool00(CPUMIPSState *env, DisasContext *ctx)
 
     switch (opcode) {
     case OPC_MXU_S32MAX:
-        /* TODO: Implement emulation of S32MAX instruction. */
-        MIPS_INVAL("OPC_MXU_S32MAX");
-        generate_exception_end(ctx, EXCP_RI);
-        break;
     case OPC_MXU_S32MIN:
-        /* TODO: Implement emulation of S32MIN instruction. */
-        MIPS_INVAL("OPC_MXU_S32MIN");
-        generate_exception_end(ctx, EXCP_RI);
+        gen_mxu_S32MAX_S32MIN(ctx);
         break;
     case OPC_MXU_D16MAX:
-        /* TODO: Implement emulation of D16MAX instruction. */
-        MIPS_INVAL("OPC_MXU_D16MAX");
-        generate_exception_end(ctx, EXCP_RI);
-        break;
     case OPC_MXU_D16MIN:
-        /* TODO: Implement emulation of D16MIN instruction. */
-        MIPS_INVAL("OPC_MXU_D16MIN");
-        generate_exception_end(ctx, EXCP_RI);
+        gen_mxu_D16MAX_D16MIN(ctx);
         break;
     case OPC_MXU_Q8MAX:
-        /* TODO: Implement emulation of Q8MAX instruction. */
-        MIPS_INVAL("OPC_MXU_Q8MAX");
-        generate_exception_end(ctx, EXCP_RI);
-        break;
     case OPC_MXU_Q8MIN:
-        /* TODO: Implement emulation of Q8MIN instruction. */
-        MIPS_INVAL("OPC_MXU_Q8MIN");
-        generate_exception_end(ctx, EXCP_RI);
+        gen_mxu_Q8MAX_Q8MIN(ctx);
         break;
     case OPC_MXU_Q8SLT:
         /* TODO: Implement emulation of Q8SLT instruction. */