diff options
Diffstat (limited to 'target/riscv/csr.c')
| -rw-r--r-- | target/riscv/csr.c | 150 |
1 files changed, 149 insertions, 1 deletions
diff --git a/target/riscv/csr.c b/target/riscv/csr.c index ab295d2ef3..0ebcca4597 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -2427,6 +2427,13 @@ static bool xiselect_cd_range(target_ulong isel) return (ISELECT_CD_FIRST <= isel && isel <= ISELECT_CD_LAST); } +static bool xiselect_ctr_range(int csrno, target_ulong isel) +{ + /* MIREG-MIREG6 for the range 0x200-0x2ff are not used by CTR. */ + return CTR_ENTRIES_FIRST <= isel && isel <= CTR_ENTRIES_LAST && + csrno < CSR_MIREG; +} + static int rmw_iprio(target_ulong xlen, target_ulong iselect, uint8_t *iprio, target_ulong *val, target_ulong new_val, @@ -2472,6 +2479,124 @@ static int rmw_iprio(target_ulong xlen, return 0; } +static int rmw_ctrsource(CPURISCVState *env, int isel, target_ulong *val, + target_ulong new_val, target_ulong wr_mask) +{ + /* + * CTR arrays are treated as circular buffers and TOS always points to next + * empty slot, keeping TOS - 1 always pointing to latest entry. Given entry + * 0 is always the latest one, traversal is a bit different here. See the + * below example. + * + * Depth = 16. + * + * idx [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [A] [B] [C] [D] [E] [F] + * TOS H + * entry 6 5 4 3 2 1 0 F E D C B A 9 8 7 + */ + const uint64_t entry = isel - CTR_ENTRIES_FIRST; + const uint64_t depth = 16 << get_field(env->sctrdepth, SCTRDEPTH_MASK); + uint64_t idx; + + /* Entry greater than depth-1 is read-only zero */ + if (entry >= depth) { + if (val) { + *val = 0; + } + return 0; + } + + idx = get_field(env->sctrstatus, SCTRSTATUS_WRPTR_MASK); + idx = (idx - entry - 1) & (depth - 1); + + if (val) { + *val = env->ctr_src[idx]; + } + + env->ctr_src[idx] = (env->ctr_src[idx] & ~wr_mask) | (new_val & wr_mask); + + return 0; +} + +static int rmw_ctrtarget(CPURISCVState *env, int isel, target_ulong *val, + target_ulong new_val, target_ulong wr_mask) +{ + /* + * CTR arrays are treated as circular buffers and TOS always points to next + * empty slot, keeping TOS - 1 always pointing to latest entry. Given entry + * 0 is always the latest one, traversal is a bit different here. See the + * below example. + * + * Depth = 16. + * + * idx [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [A] [B] [C] [D] [E] [F] + * head H + * entry 6 5 4 3 2 1 0 F E D C B A 9 8 7 + */ + const uint64_t entry = isel - CTR_ENTRIES_FIRST; + const uint64_t depth = 16 << get_field(env->sctrdepth, SCTRDEPTH_MASK); + uint64_t idx; + + /* Entry greater than depth-1 is read-only zero */ + if (entry >= depth) { + if (val) { + *val = 0; + } + return 0; + } + + idx = get_field(env->sctrstatus, SCTRSTATUS_WRPTR_MASK); + idx = (idx - entry - 1) & (depth - 1); + + if (val) { + *val = env->ctr_dst[idx]; + } + + env->ctr_dst[idx] = (env->ctr_dst[idx] & ~wr_mask) | (new_val & wr_mask); + + return 0; +} + +static int rmw_ctrdata(CPURISCVState *env, int isel, target_ulong *val, + target_ulong new_val, target_ulong wr_mask) +{ + /* + * CTR arrays are treated as circular buffers and TOS always points to next + * empty slot, keeping TOS - 1 always pointing to latest entry. Given entry + * 0 is always the latest one, traversal is a bit different here. See the + * below example. + * + * Depth = 16. + * + * idx [0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [A] [B] [C] [D] [E] [F] + * head H + * entry 6 5 4 3 2 1 0 F E D C B A 9 8 7 + */ + const uint64_t entry = isel - CTR_ENTRIES_FIRST; + const uint64_t mask = wr_mask & CTRDATA_MASK; + const uint64_t depth = 16 << get_field(env->sctrdepth, SCTRDEPTH_MASK); + uint64_t idx; + + /* Entry greater than depth-1 is read-only zero */ + if (entry >= depth) { + if (val) { + *val = 0; + } + return 0; + } + + idx = get_field(env->sctrstatus, SCTRSTATUS_WRPTR_MASK); + idx = (idx - entry - 1) & (depth - 1); + + if (val) { + *val = env->ctr_data[idx]; + } + + env->ctr_data[idx] = (env->ctr_data[idx] & ~mask) | (new_val & mask); + + return 0; +} + static RISCVException rmw_xireg_aia(CPURISCVState *env, int csrno, target_ulong isel, target_ulong *val, target_ulong new_val, target_ulong wr_mask) @@ -2624,6 +2749,27 @@ done: return ret; } +static int rmw_xireg_ctr(CPURISCVState *env, int csrno, + target_ulong isel, target_ulong *val, + target_ulong new_val, target_ulong wr_mask) +{ + if (!riscv_cpu_cfg(env)->ext_smctr && !riscv_cpu_cfg(env)->ext_ssctr) { + return -EINVAL; + } + + if (csrno == CSR_SIREG || csrno == CSR_VSIREG) { + return rmw_ctrsource(env, isel, val, new_val, wr_mask); + } else if (csrno == CSR_SIREG2 || csrno == CSR_VSIREG2) { + return rmw_ctrtarget(env, isel, val, new_val, wr_mask); + } else if (csrno == CSR_SIREG3 || csrno == CSR_VSIREG3) { + return rmw_ctrdata(env, isel, val, new_val, wr_mask); + } else if (val) { + *val = 0; + } + + return 0; +} + /* * rmw_xireg_csrind: Perform indirect access to xireg and xireg2-xireg6 * @@ -2635,11 +2781,13 @@ static int rmw_xireg_csrind(CPURISCVState *env, int csrno, target_ulong isel, target_ulong *val, target_ulong new_val, target_ulong wr_mask) { - int ret = -EINVAL; bool virt = csrno == CSR_VSIREG ? true : false; + int ret = -EINVAL; if (xiselect_cd_range(isel)) { ret = rmw_xireg_cd(env, csrno, isel, val, new_val, wr_mask); + } else if (xiselect_ctr_range(csrno, isel)) { + ret = rmw_xireg_ctr(env, csrno, isel, val, new_val, wr_mask); } else { /* * As per the specification, access to unimplented region is undefined |