From 54b349aee5202693f31a64a84e01a64763a9cf37 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@imgtec.com>
Date: Sun, 4 Mar 2018 00:37:32 -0500
Subject: [PATCH] target/mips: Decode microMIPS EVA load & store instructions

Implement decoding of microMIPS EVA load and store instruction groups in
the POOL31C pool. These use the same gen_ld(), gen_st(), gen_st_cond()
helpers as the MIPS32 decoding, passing the equivalent MIPS32 opcodes as
opc.

Backports commit 8fffc64696783b1ff1d17262d098976479895660 from qemu
---
 qemu/target/mips/translate.c | 119 +++++++++++++++++++++++++++++++++--
 1 file changed, 115 insertions(+), 4 deletions(-)

diff --git a/qemu/target/mips/translate.c b/qemu/target/mips/translate.c
index 9475fc01..0950cf12 100644
--- a/qemu/target/mips/translate.c
+++ b/qemu/target/mips/translate.c
@@ -12636,19 +12636,45 @@ enum {
     LWR = 0x1,
     SWR = 0x9,
     PREF = 0x2,
-    /* 0xa is reserved */
+    ST_EVA = 0xa,
     LL = 0x3,
     SC = 0xb,
     LDL = 0x4,
     SDL = 0xc,
     LDR = 0x5,
     SDR = 0xd,
-    /* 0x6 is reserved */
+    LD_EVA = 0x6,
     LWU = 0xe,
     LLD = 0x7,
     SCD = 0xf
 };
 
+/* POOL32C LD-EVA encoding of minor opcode field (bits 11..9) */
+
+enum {
+    LBUE = 0x0,
+    LHUE = 0x1,
+    LWLE = 0x2,
+    LWRE = 0x3,
+    LBE = 0x4,
+    LHE = 0x5,
+    LLE = 0x6,
+    LWE = 0x7,
+};
+
+/* POOL32C ST-EVA encoding of minor opcode field (bits 11..9) */
+
+enum {
+    SWLE = 0x0,
+    SWRE = 0x1,
+    PREFE = 0x2,
+    CACHEE = 0x3,
+    SBE = 0x4,
+    SHE = 0x5,
+    SCE = 0x6,
+    SWE = 0x7,
+};
+
 /* POOL32F encoding of minor opcode field (bits 5..0) */
 
 enum {
@@ -13950,7 +13976,7 @@ static void decode_micromips32_opc(CPUMIPSState *env, DisasContext *ctx)
     uint16_t insn;
     int rt, rs, rd, rr;
     int16_t imm;
-    uint32_t op, minor, mips32_op;
+    uint32_t op, minor, minor2, mips32_op;
     uint32_t cond, fmt, cc;
 
     insn = cpu_lduw_code(env, ctx->pc + 2);
@@ -14895,7 +14921,7 @@ static void decode_micromips32_opc(CPUMIPSState *env, DisasContext *ctx)
             gen_ld(ctx, mips32_op, rt, rs, offset);
             break;
         do_st_lr:
-            gen_st(ctx, mips32_op, rt, rs, SIMM(ctx->opcode, 0, 12));
+            gen_st(ctx, mips32_op, rt, rs, offset);
             break;
         case SC:
             gen_st_cond(ctx, OPC_SC, rt, rs, offset);
@@ -14907,6 +14933,91 @@ static void decode_micromips32_opc(CPUMIPSState *env, DisasContext *ctx)
             gen_st_cond(ctx, OPC_SCD, rt, rs, offset);
             break;
 #endif
+        case LD_EVA:
+            if (!ctx->eva) {
+                MIPS_INVAL("pool32c ld-eva");
+                generate_exception_end(ctx, EXCP_RI);
+                break;
+            }
+            check_cp0_enabled(ctx);
+
+            minor2 = (ctx->opcode >> 9) & 0x7;
+            offset = sextract32(ctx->opcode, 0, 9);
+            switch (minor2) {
+            case LBUE:
+                mips32_op = OPC_LBUE;
+                goto do_ld_lr;
+            case LHUE:
+                mips32_op = OPC_LHUE;
+                goto do_ld_lr;
+            case LWLE:
+                check_insn_opc_removed(ctx, ISA_MIPS32R6);
+                mips32_op = OPC_LWLE;
+                goto do_ld_lr;
+            case LWRE:
+                check_insn_opc_removed(ctx, ISA_MIPS32R6);
+                mips32_op = OPC_LWRE;
+                goto do_ld_lr;
+            case LBE:
+                mips32_op = OPC_LBE;
+                goto do_ld_lr;
+            case LHE:
+                mips32_op = OPC_LHE;
+                goto do_ld_lr;
+            case LLE:
+                mips32_op = OPC_LLE;
+                goto do_ld_lr;
+            case LWE:
+                mips32_op = OPC_LWE;
+                goto do_ld_lr;
+            };
+            break;
+        case ST_EVA:
+            if (!ctx->eva) {
+                MIPS_INVAL("pool32c st-eva");
+                generate_exception_end(ctx, EXCP_RI);
+                break;
+            }
+            check_cp0_enabled(ctx);
+
+            minor2 = (ctx->opcode >> 9) & 0x7;
+            offset = sextract32(ctx->opcode, 0, 9);
+            switch (minor2) {
+            case SWLE:
+                check_insn_opc_removed(ctx, ISA_MIPS32R6);
+                mips32_op = OPC_SWLE;
+                goto do_st_lr;
+            case SWRE:
+                check_insn_opc_removed(ctx, ISA_MIPS32R6);
+                mips32_op = OPC_SWRE;
+                goto do_st_lr;
+            case PREFE:
+                /* Treat as no-op */
+                if ((ctx->insn_flags & ISA_MIPS32R6) && (rt >= 24)) {
+                    /* hint codes 24-31 are reserved and signal RI */
+                    generate_exception(ctx, EXCP_RI);
+                }
+                break;
+            case CACHEE:
+                /* Treat as no-op */
+                if (ctx->hflags & MIPS_HFLAG_ITC_CACHE) {
+                    gen_cache_operation(ctx, rt, rs, offset);
+                }
+                break;
+            case SBE:
+                mips32_op = OPC_SBE;
+                goto do_st_lr;
+            case SHE:
+                mips32_op = OPC_SHE;
+                goto do_st_lr;
+            case SCE:
+                gen_st_cond(ctx, OPC_SCE, rt, rs, offset);
+                break;
+            case SWE:
+                mips32_op = OPC_SWE;
+                goto do_st_lr;
+            };
+            break;
         case PREF:
             /* Treat as no-op */
             if ((ctx->insn_flags & ISA_MIPS32R6) && (rt >= 24)) {