diff options
Diffstat (limited to 'kernel/arch/mips/math-emu/cp1emu.c')
| -rw-r--r-- | kernel/arch/mips/math-emu/cp1emu.c | 2218 |
1 files changed, 2218 insertions, 0 deletions
diff --git a/kernel/arch/mips/math-emu/cp1emu.c b/kernel/arch/mips/math-emu/cp1emu.c new file mode 100644 index 000000000..22b9b2cb9 --- /dev/null +++ b/kernel/arch/mips/math-emu/cp1emu.c @@ -0,0 +1,2218 @@ +/* + * cp1emu.c: a MIPS coprocessor 1 (FPU) instruction emulator + * + * MIPS floating point support + * Copyright (C) 1994-2000 Algorithmics Ltd. + * + * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com + * Copyright (C) 2000 MIPS Technologies, Inc. + * + * This program is free software; you can distribute it and/or modify it + * under the terms of the GNU General Public License (Version 2) as + * published by the Free Software Foundation. + * + * This program is distributed in the hope 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, write to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * A complete emulator for MIPS coprocessor 1 instructions. This is + * required for #float(switch) or #float(trap), where it catches all + * COP1 instructions via the "CoProcessor Unusable" exception. + * + * More surprisingly it is also required for #float(ieee), to help out + * the hardware FPU at the boundaries of the IEEE-754 representation + * (denormalised values, infinities, underflow, etc). It is made + * quite nasty because emulation of some non-COP1 instructions is + * required, e.g. in branch delay slots. + * + * Note if you know that you won't have an FPU, then you'll get much + * better performance by compiling with -msoft-float! + */ +#include <linux/sched.h> +#include <linux/debugfs.h> +#include <linux/kconfig.h> +#include <linux/percpu-defs.h> +#include <linux/perf_event.h> + +#include <asm/branch.h> +#include <asm/inst.h> +#include <asm/ptrace.h> +#include <asm/signal.h> +#include <asm/uaccess.h> + +#include <asm/cpu-info.h> +#include <asm/processor.h> +#include <asm/fpu_emulator.h> +#include <asm/fpu.h> +#include <asm/mips-r2-to-r6-emul.h> + +#include "ieee754.h" + +/* Function which emulates a floating point instruction. */ + +static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *, + mips_instruction); + +static int fpux_emu(struct pt_regs *, + struct mips_fpu_struct *, mips_instruction, void *__user *); + +/* Control registers */ + +#define FPCREG_RID 0 /* $0 = revision id */ +#define FPCREG_FCCR 25 /* $25 = fccr */ +#define FPCREG_FEXR 26 /* $26 = fexr */ +#define FPCREG_FENR 28 /* $28 = fenr */ +#define FPCREG_CSR 31 /* $31 = csr */ + +/* convert condition code register number to csr bit */ +const unsigned int fpucondbit[8] = { + FPU_CSR_COND, + FPU_CSR_COND1, + FPU_CSR_COND2, + FPU_CSR_COND3, + FPU_CSR_COND4, + FPU_CSR_COND5, + FPU_CSR_COND6, + FPU_CSR_COND7 +}; + +/* (microMIPS) Convert certain microMIPS instructions to MIPS32 format. */ +static const int sd_format[] = {16, 17, 0, 0, 0, 0, 0, 0}; +static const int sdps_format[] = {16, 17, 22, 0, 0, 0, 0, 0}; +static const int dwl_format[] = {17, 20, 21, 0, 0, 0, 0, 0}; +static const int swl_format[] = {16, 20, 21, 0, 0, 0, 0, 0}; + +/* + * This functions translates a 32-bit microMIPS instruction + * into a 32-bit MIPS32 instruction. Returns 0 on success + * and SIGILL otherwise. + */ +static int microMIPS32_to_MIPS32(union mips_instruction *insn_ptr) +{ + union mips_instruction insn = *insn_ptr; + union mips_instruction mips32_insn = insn; + int func, fmt, op; + + switch (insn.mm_i_format.opcode) { + case mm_ldc132_op: + mips32_insn.mm_i_format.opcode = ldc1_op; + mips32_insn.mm_i_format.rt = insn.mm_i_format.rs; + mips32_insn.mm_i_format.rs = insn.mm_i_format.rt; + break; + case mm_lwc132_op: + mips32_insn.mm_i_format.opcode = lwc1_op; + mips32_insn.mm_i_format.rt = insn.mm_i_format.rs; + mips32_insn.mm_i_format.rs = insn.mm_i_format.rt; + break; + case mm_sdc132_op: + mips32_insn.mm_i_format.opcode = sdc1_op; + mips32_insn.mm_i_format.rt = insn.mm_i_format.rs; + mips32_insn.mm_i_format.rs = insn.mm_i_format.rt; + break; + case mm_swc132_op: + mips32_insn.mm_i_format.opcode = swc1_op; + mips32_insn.mm_i_format.rt = insn.mm_i_format.rs; + mips32_insn.mm_i_format.rs = insn.mm_i_format.rt; + break; + case mm_pool32i_op: + /* NOTE: offset is << by 1 if in microMIPS mode. */ + if ((insn.mm_i_format.rt == mm_bc1f_op) || + (insn.mm_i_format.rt == mm_bc1t_op)) { + mips32_insn.fb_format.opcode = cop1_op; + mips32_insn.fb_format.bc = bc_op; + mips32_insn.fb_format.flag = + (insn.mm_i_format.rt == mm_bc1t_op) ? 1 : 0; + } else + return SIGILL; + break; + case mm_pool32f_op: + switch (insn.mm_fp0_format.func) { + case mm_32f_01_op: + case mm_32f_11_op: + case mm_32f_02_op: + case mm_32f_12_op: + case mm_32f_41_op: + case mm_32f_51_op: + case mm_32f_42_op: + case mm_32f_52_op: + op = insn.mm_fp0_format.func; + if (op == mm_32f_01_op) + func = madd_s_op; + else if (op == mm_32f_11_op) + func = madd_d_op; + else if (op == mm_32f_02_op) + func = nmadd_s_op; + else if (op == mm_32f_12_op) + func = nmadd_d_op; + else if (op == mm_32f_41_op) + func = msub_s_op; + else if (op == mm_32f_51_op) + func = msub_d_op; + else if (op == mm_32f_42_op) + func = nmsub_s_op; + else + func = nmsub_d_op; + mips32_insn.fp6_format.opcode = cop1x_op; + mips32_insn.fp6_format.fr = insn.mm_fp6_format.fr; + mips32_insn.fp6_format.ft = insn.mm_fp6_format.ft; + mips32_insn.fp6_format.fs = insn.mm_fp6_format.fs; + mips32_insn.fp6_format.fd = insn.mm_fp6_format.fd; + mips32_insn.fp6_format.func = func; + break; + case mm_32f_10_op: + func = -1; /* Invalid */ + op = insn.mm_fp5_format.op & 0x7; + if (op == mm_ldxc1_op) + func = ldxc1_op; + else if (op == mm_sdxc1_op) + func = sdxc1_op; + else if (op == mm_lwxc1_op) + func = lwxc1_op; + else if (op == mm_swxc1_op) + func = swxc1_op; + + if (func != -1) { + mips32_insn.r_format.opcode = cop1x_op; + mips32_insn.r_format.rs = + insn.mm_fp5_format.base; + mips32_insn.r_format.rt = + insn.mm_fp5_format.index; + mips32_insn.r_format.rd = 0; + mips32_insn.r_format.re = insn.mm_fp5_format.fd; + mips32_insn.r_format.func = func; + } else + return SIGILL; + break; + case mm_32f_40_op: + op = -1; /* Invalid */ + if (insn.mm_fp2_format.op == mm_fmovt_op) + op = 1; + else if (insn.mm_fp2_format.op == mm_fmovf_op) + op = 0; + if (op != -1) { + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = + sdps_format[insn.mm_fp2_format.fmt]; + mips32_insn.fp0_format.ft = + (insn.mm_fp2_format.cc<<2) + op; + mips32_insn.fp0_format.fs = + insn.mm_fp2_format.fs; + mips32_insn.fp0_format.fd = + insn.mm_fp2_format.fd; + mips32_insn.fp0_format.func = fmovc_op; + } else + return SIGILL; + break; + case mm_32f_60_op: + func = -1; /* Invalid */ + if (insn.mm_fp0_format.op == mm_fadd_op) + func = fadd_op; + else if (insn.mm_fp0_format.op == mm_fsub_op) + func = fsub_op; + else if (insn.mm_fp0_format.op == mm_fmul_op) + func = fmul_op; + else if (insn.mm_fp0_format.op == mm_fdiv_op) + func = fdiv_op; + if (func != -1) { + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = + sdps_format[insn.mm_fp0_format.fmt]; + mips32_insn.fp0_format.ft = + insn.mm_fp0_format.ft; + mips32_insn.fp0_format.fs = + insn.mm_fp0_format.fs; + mips32_insn.fp0_format.fd = + insn.mm_fp0_format.fd; + mips32_insn.fp0_format.func = func; + } else + return SIGILL; + break; + case mm_32f_70_op: + func = -1; /* Invalid */ + if (insn.mm_fp0_format.op == mm_fmovn_op) + func = fmovn_op; + else if (insn.mm_fp0_format.op == mm_fmovz_op) + func = fmovz_op; + if (func != -1) { + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = + sdps_format[insn.mm_fp0_format.fmt]; + mips32_insn.fp0_format.ft = + insn.mm_fp0_format.ft; + mips32_insn.fp0_format.fs = + insn.mm_fp0_format.fs; + mips32_insn.fp0_format.fd = + insn.mm_fp0_format.fd; + mips32_insn.fp0_format.func = func; + } else + return SIGILL; + break; + case mm_32f_73_op: /* POOL32FXF */ + switch (insn.mm_fp1_format.op) { + case mm_movf0_op: + case mm_movf1_op: + case mm_movt0_op: + case mm_movt1_op: + if ((insn.mm_fp1_format.op & 0x7f) == + mm_movf0_op) + op = 0; + else + op = 1; + mips32_insn.r_format.opcode = spec_op; + mips32_insn.r_format.rs = insn.mm_fp4_format.fs; + mips32_insn.r_format.rt = + (insn.mm_fp4_format.cc << 2) + op; + mips32_insn.r_format.rd = insn.mm_fp4_format.rt; + mips32_insn.r_format.re = 0; + mips32_insn.r_format.func = movc_op; + break; + case mm_fcvtd0_op: + case mm_fcvtd1_op: + case mm_fcvts0_op: + case mm_fcvts1_op: + if ((insn.mm_fp1_format.op & 0x7f) == + mm_fcvtd0_op) { + func = fcvtd_op; + fmt = swl_format[insn.mm_fp3_format.fmt]; + } else { + func = fcvts_op; + fmt = dwl_format[insn.mm_fp3_format.fmt]; + } + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = fmt; + mips32_insn.fp0_format.ft = 0; + mips32_insn.fp0_format.fs = + insn.mm_fp3_format.fs; + mips32_insn.fp0_format.fd = + insn.mm_fp3_format.rt; + mips32_insn.fp0_format.func = func; + break; + case mm_fmov0_op: + case mm_fmov1_op: + case mm_fabs0_op: + case mm_fabs1_op: + case mm_fneg0_op: + case mm_fneg1_op: + if ((insn.mm_fp1_format.op & 0x7f) == + mm_fmov0_op) + func = fmov_op; + else if ((insn.mm_fp1_format.op & 0x7f) == + mm_fabs0_op) + func = fabs_op; + else + func = fneg_op; + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = + sdps_format[insn.mm_fp3_format.fmt]; + mips32_insn.fp0_format.ft = 0; + mips32_insn.fp0_format.fs = + insn.mm_fp3_format.fs; + mips32_insn.fp0_format.fd = + insn.mm_fp3_format.rt; + mips32_insn.fp0_format.func = func; + break; + case mm_ffloorl_op: + case mm_ffloorw_op: + case mm_fceill_op: + case mm_fceilw_op: + case mm_ftruncl_op: + case mm_ftruncw_op: + case mm_froundl_op: + case mm_froundw_op: + case mm_fcvtl_op: + case mm_fcvtw_op: + if (insn.mm_fp1_format.op == mm_ffloorl_op) + func = ffloorl_op; + else if (insn.mm_fp1_format.op == mm_ffloorw_op) + func = ffloor_op; + else if (insn.mm_fp1_format.op == mm_fceill_op) + func = fceill_op; + else if (insn.mm_fp1_format.op == mm_fceilw_op) + func = fceil_op; + else if (insn.mm_fp1_format.op == mm_ftruncl_op) + func = ftruncl_op; + else if (insn.mm_fp1_format.op == mm_ftruncw_op) + func = ftrunc_op; + else if (insn.mm_fp1_format.op == mm_froundl_op) + func = froundl_op; + else if (insn.mm_fp1_format.op == mm_froundw_op) + func = fround_op; + else if (insn.mm_fp1_format.op == mm_fcvtl_op) + func = fcvtl_op; + else + func = fcvtw_op; + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = + sd_format[insn.mm_fp1_format.fmt]; + mips32_insn.fp0_format.ft = 0; + mips32_insn.fp0_format.fs = + insn.mm_fp1_format.fs; + mips32_insn.fp0_format.fd = + insn.mm_fp1_format.rt; + mips32_insn.fp0_format.func = func; + break; + case mm_frsqrt_op: + case mm_fsqrt_op: + case mm_frecip_op: + if (insn.mm_fp1_format.op == mm_frsqrt_op) + func = frsqrt_op; + else if (insn.mm_fp1_format.op == mm_fsqrt_op) + func = fsqrt_op; + else + func = frecip_op; + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = + sdps_format[insn.mm_fp1_format.fmt]; + mips32_insn.fp0_format.ft = 0; + mips32_insn.fp0_format.fs = + insn.mm_fp1_format.fs; + mips32_insn.fp0_format.fd = + insn.mm_fp1_format.rt; + mips32_insn.fp0_format.func = func; + break; + case mm_mfc1_op: + case mm_mtc1_op: + case mm_cfc1_op: + case mm_ctc1_op: + case mm_mfhc1_op: + case mm_mthc1_op: + if (insn.mm_fp1_format.op == mm_mfc1_op) + op = mfc_op; + else if (insn.mm_fp1_format.op == mm_mtc1_op) + op = mtc_op; + else if (insn.mm_fp1_format.op == mm_cfc1_op) + op = cfc_op; + else if (insn.mm_fp1_format.op == mm_ctc1_op) + op = ctc_op; + else if (insn.mm_fp1_format.op == mm_mfhc1_op) + op = mfhc_op; + else + op = mthc_op; + mips32_insn.fp1_format.opcode = cop1_op; + mips32_insn.fp1_format.op = op; + mips32_insn.fp1_format.rt = + insn.mm_fp1_format.rt; + mips32_insn.fp1_format.fs = + insn.mm_fp1_format.fs; + mips32_insn.fp1_format.fd = 0; + mips32_insn.fp1_format.func = 0; + break; + default: + return SIGILL; + } + break; + case mm_32f_74_op: /* c.cond.fmt */ + mips32_insn.fp0_format.opcode = cop1_op; + mips32_insn.fp0_format.fmt = + sdps_format[insn.mm_fp4_format.fmt]; + mips32_insn.fp0_format.ft = insn.mm_fp4_format.rt; + mips32_insn.fp0_format.fs = insn.mm_fp4_format.fs; + mips32_insn.fp0_format.fd = insn.mm_fp4_format.cc << 2; + mips32_insn.fp0_format.func = + insn.mm_fp4_format.cond | MM_MIPS32_COND_FC; + break; + default: + return SIGILL; + } + break; + default: + return SIGILL; + } + + *insn_ptr = mips32_insn; + return 0; +} + +/* + * Redundant with logic already in kernel/branch.c, + * embedded in compute_return_epc. At some point, + * a single subroutine should be used across both + * modules. + */ +static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, + unsigned long *contpc) +{ + union mips_instruction insn = (union mips_instruction)dec_insn.insn; + unsigned int fcr31; + unsigned int bit = 0; + + switch (insn.i_format.opcode) { + case spec_op: + switch (insn.r_format.func) { + case jalr_op: + regs->regs[insn.r_format.rd] = + regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + /* Fall through */ + case jr_op: + /* For R6, JR already emulated in jalr_op */ + if (NO_R6EMU && insn.r_format.opcode == jr_op) + break; + *contpc = regs->regs[insn.r_format.rs]; + return 1; + } + break; + case bcond_op: + switch (insn.i_format.rt) { + case bltzal_op: + case bltzall_op: + if (NO_R6EMU && (insn.i_format.rs || + insn.i_format.rt == bltzall_op)) + break; + + regs->regs[31] = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + /* Fall through */ + case bltzl_op: + if (NO_R6EMU) + break; + case bltz_op: + if ((long)regs->regs[insn.i_format.rs] < 0) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + case bgezal_op: + case bgezall_op: + if (NO_R6EMU && (insn.i_format.rs || + insn.i_format.rt == bgezall_op)) + break; + + regs->regs[31] = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + /* Fall through */ + case bgezl_op: + if (NO_R6EMU) + break; + case bgez_op: + if ((long)regs->regs[insn.i_format.rs] >= 0) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + } + break; + case jalx_op: + set_isa16_mode(bit); + case jal_op: + regs->regs[31] = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + /* Fall through */ + case j_op: + *contpc = regs->cp0_epc + dec_insn.pc_inc; + *contpc >>= 28; + *contpc <<= 28; + *contpc |= (insn.j_format.target << 2); + /* Set microMIPS mode bit: XOR for jalx. */ + *contpc ^= bit; + return 1; + case beql_op: + if (NO_R6EMU) + break; + case beq_op: + if (regs->regs[insn.i_format.rs] == + regs->regs[insn.i_format.rt]) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + case bnel_op: + if (NO_R6EMU) + break; + case bne_op: + if (regs->regs[insn.i_format.rs] != + regs->regs[insn.i_format.rt]) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + case blezl_op: + if (NO_R6EMU) + break; + case blez_op: + + /* + * Compact branches for R6 for the + * blez and blezl opcodes. + * BLEZ | rs = 0 | rt != 0 == BLEZALC + * BLEZ | rs = rt != 0 == BGEZALC + * BLEZ | rs != 0 | rt != 0 == BGEUC + * BLEZL | rs = 0 | rt != 0 == BLEZC + * BLEZL | rs = rt != 0 == BGEZC + * BLEZL | rs != 0 | rt != 0 == BGEC + * + * For real BLEZ{,L}, rt is always 0. + */ + if (cpu_has_mips_r6 && insn.i_format.rt) { + if ((insn.i_format.opcode == blez_op) && + ((!insn.i_format.rs && insn.i_format.rt) || + (insn.i_format.rs == insn.i_format.rt))) + regs->regs[31] = regs->cp0_epc + + dec_insn.pc_inc; + *contpc = regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; + } + if ((long)regs->regs[insn.i_format.rs] <= 0) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + case bgtzl_op: + if (NO_R6EMU) + break; + case bgtz_op: + /* + * Compact branches for R6 for the + * bgtz and bgtzl opcodes. + * BGTZ | rs = 0 | rt != 0 == BGTZALC + * BGTZ | rs = rt != 0 == BLTZALC + * BGTZ | rs != 0 | rt != 0 == BLTUC + * BGTZL | rs = 0 | rt != 0 == BGTZC + * BGTZL | rs = rt != 0 == BLTZC + * BGTZL | rs != 0 | rt != 0 == BLTC + * + * *ZALC varint for BGTZ &&& rt != 0 + * For real GTZ{,L}, rt is always 0. + */ + if (cpu_has_mips_r6 && insn.i_format.rt) { + if ((insn.i_format.opcode == blez_op) && + ((!insn.i_format.rs && insn.i_format.rt) || + (insn.i_format.rs == insn.i_format.rt))) + regs->regs[31] = regs->cp0_epc + + dec_insn.pc_inc; + *contpc = regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; + } + + if ((long)regs->regs[insn.i_format.rs] > 0) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + case cbcond0_op: + case cbcond1_op: + if (!cpu_has_mips_r6) + break; + if (insn.i_format.rt && !insn.i_format.rs) + regs->regs[31] = regs->cp0_epc + 4; + *contpc = regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; +#ifdef CONFIG_CPU_CAVIUM_OCTEON + case lwc2_op: /* This is bbit0 on Octeon */ + if ((regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt)) == 0) + *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + 8; + return 1; + case ldc2_op: /* This is bbit032 on Octeon */ + if ((regs->regs[insn.i_format.rs] & (1ull<<(insn.i_format.rt + 32))) == 0) + *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + 8; + return 1; + case swc2_op: /* This is bbit1 on Octeon */ + if (regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt)) + *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + 8; + return 1; + case sdc2_op: /* This is bbit132 on Octeon */ + if (regs->regs[insn.i_format.rs] & (1ull<<(insn.i_format.rt + 32))) + *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + 8; + return 1; +#else + case bc6_op: + /* + * Only valid for MIPS R6 but we can still end up + * here from a broken userland so just tell emulator + * this is not a branch and let it break later on. + */ + if (!cpu_has_mips_r6) + break; + *contpc = regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; + case balc6_op: + if (!cpu_has_mips_r6) + break; + regs->regs[31] = regs->cp0_epc + 4; + *contpc = regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; + case beqzcjic_op: + if (!cpu_has_mips_r6) + break; + *contpc = regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; + case bnezcjialc_op: + if (!cpu_has_mips_r6) + break; + if (!insn.i_format.rs) + regs->regs[31] = regs->cp0_epc + 4; + *contpc = regs->cp0_epc + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; +#endif + case cop0_op: + case cop1_op: + /* Need to check for R6 bc1nez and bc1eqz branches */ + if (cpu_has_mips_r6 && + ((insn.i_format.rs == bc1eqz_op) || + (insn.i_format.rs == bc1nez_op))) { + bit = 0; + switch (insn.i_format.rs) { + case bc1eqz_op: + if (get_fpr32(¤t->thread.fpu.fpr[insn.i_format.rt], 0) & 0x1) + bit = 1; + break; + case bc1nez_op: + if (!(get_fpr32(¤t->thread.fpu.fpr[insn.i_format.rt], 0) & 0x1)) + bit = 1; + break; + } + if (bit) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + + return 1; + } + /* R2/R6 compatible cop1 instruction. Fall through */ + case cop2_op: + case cop1x_op: + if (insn.i_format.rs == bc_op) { + preempt_disable(); + if (is_fpu_owner()) + fcr31 = read_32bit_cp1_register(CP1_STATUS); + else + fcr31 = current->thread.fpu.fcr31; + preempt_enable(); + + bit = (insn.i_format.rt >> 2); + bit += (bit != 0); + bit += 23; + switch (insn.i_format.rt & 3) { + case 0: /* bc1f */ + case 2: /* bc1fl */ + if (~fcr31 & (1 << bit)) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + case 1: /* bc1t */ + case 3: /* bc1tl */ + if (fcr31 & (1 << bit)) + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + (insn.i_format.simmediate << 2); + else + *contpc = regs->cp0_epc + + dec_insn.pc_inc + + dec_insn.next_pc_inc; + return 1; + } + } + break; + } + return 0; +} + +/* + * In the Linux kernel, we support selection of FPR format on the + * basis of the Status.FR bit. If an FPU is not present, the FR bit + * is hardwired to zero, which would imply a 32-bit FPU even for + * 64-bit CPUs so we rather look at TIF_32BIT_FPREGS. + * FPU emu is slow and bulky and optimizing this function offers fairly + * sizeable benefits so we try to be clever and make this function return + * a constant whenever possible, that is on 64-bit kernels without O32 + * compatibility enabled and on 32-bit without 64-bit FPU support. + */ +static inline int cop1_64bit(struct pt_regs *xcp) +{ + if (config_enabled(CONFIG_64BIT) && !config_enabled(CONFIG_MIPS32_O32)) + return 1; + else if (config_enabled(CONFIG_32BIT) && + !config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT)) + return 0; + + return !test_thread_flag(TIF_32BIT_FPREGS); +} + +static inline bool hybrid_fprs(void) +{ + return test_thread_flag(TIF_HYBRID_FPREGS); +} + +#define SIFROMREG(si, x) \ +do { \ + if (cop1_64bit(xcp) && !hybrid_fprs()) \ + (si) = (int)get_fpr32(&ctx->fpr[x], 0); \ + else \ + (si) = (int)get_fpr32(&ctx->fpr[(x) & ~1], (x) & 1); \ +} while (0) + +#define SITOREG(si, x) \ +do { \ + if (cop1_64bit(xcp) && !hybrid_fprs()) { \ + unsigned i; \ + set_fpr32(&ctx->fpr[x], 0, si); \ + for (i = 1; i < ARRAY_SIZE(ctx->fpr[x].val32); i++) \ + set_fpr32(&ctx->fpr[x], i, 0); \ + } else { \ + set_fpr32(&ctx->fpr[(x) & ~1], (x) & 1, si); \ + } \ +} while (0) + +#define SIFROMHREG(si, x) ((si) = (int)get_fpr32(&ctx->fpr[x], 1)) + +#define SITOHREG(si, x) \ +do { \ + unsigned i; \ + set_fpr32(&ctx->fpr[x], 1, si); \ + for (i = 2; i < ARRAY_SIZE(ctx->fpr[x].val32); i++) \ + set_fpr32(&ctx->fpr[x], i, 0); \ +} while (0) + +#define DIFROMREG(di, x) \ + ((di) = get_fpr64(&ctx->fpr[(x) & ~(cop1_64bit(xcp) == 0)], 0)) + +#define DITOREG(di, x) \ +do { \ + unsigned fpr, i; \ + fpr = (x) & ~(cop1_64bit(xcp) == 0); \ + set_fpr64(&ctx->fpr[fpr], 0, di); \ + for (i = 1; i < ARRAY_SIZE(ctx->fpr[x].val64); i++) \ + set_fpr64(&ctx->fpr[fpr], i, 0); \ +} while (0) + +#define SPFROMREG(sp, x) SIFROMREG((sp).bits, x) +#define SPTOREG(sp, x) SITOREG((sp).bits, x) +#define DPFROMREG(dp, x) DIFROMREG((dp).bits, x) +#define DPTOREG(dp, x) DITOREG((dp).bits, x) + +/* + * Emulate a CFC1 instruction. + */ +static inline void cop1_cfc(struct pt_regs *xcp, struct mips_fpu_struct *ctx, + mips_instruction ir) +{ + u32 fcr31 = ctx->fcr31; + u32 value = 0; + + switch (MIPSInst_RD(ir)) { + case FPCREG_CSR: + value = fcr31; + pr_debug("%p gpr[%d]<-csr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + break; + + case FPCREG_FENR: + if (!cpu_has_mips_r) + break; + value = (fcr31 >> (FPU_CSR_FS_S - MIPS_FENR_FS_S)) & + MIPS_FENR_FS; + value |= fcr31 & (FPU_CSR_ALL_E | FPU_CSR_RM); + pr_debug("%p gpr[%d]<-enr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + break; + + case FPCREG_FEXR: + if (!cpu_has_mips_r) + break; + value = fcr31 & (FPU_CSR_ALL_X | FPU_CSR_ALL_S); + pr_debug("%p gpr[%d]<-exr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + break; + + case FPCREG_FCCR: + if (!cpu_has_mips_r) + break; + value = (fcr31 >> (FPU_CSR_COND_S - MIPS_FCCR_COND0_S)) & + MIPS_FCCR_COND0; + value |= (fcr31 >> (FPU_CSR_COND1_S - MIPS_FCCR_COND1_S)) & + (MIPS_FCCR_CONDX & ~MIPS_FCCR_COND0); + pr_debug("%p gpr[%d]<-ccr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + break; + + case FPCREG_RID: + value = boot_cpu_data.fpu_id; + break; + + default: + break; + } + + if (MIPSInst_RT(ir)) + xcp->regs[MIPSInst_RT(ir)] = value; +} + +/* + * Emulate a CTC1 instruction. + */ +static inline void cop1_ctc(struct pt_regs *xcp, struct mips_fpu_struct *ctx, + mips_instruction ir) +{ + u32 fcr31 = ctx->fcr31; + u32 value; + u32 mask; + + if (MIPSInst_RT(ir) == 0) + value = 0; + else + value = xcp->regs[MIPSInst_RT(ir)]; + + switch (MIPSInst_RD(ir)) { + case FPCREG_CSR: + pr_debug("%p gpr[%d]->csr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + + /* Preserve read-only bits. */ + mask = boot_cpu_data.fpu_msk31; + fcr31 = (value & ~mask) | (fcr31 & mask); + break; + + case FPCREG_FENR: + if (!cpu_has_mips_r) + break; + pr_debug("%p gpr[%d]->enr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + fcr31 &= ~(FPU_CSR_FS | FPU_CSR_ALL_E | FPU_CSR_RM); + fcr31 |= (value << (FPU_CSR_FS_S - MIPS_FENR_FS_S)) & + FPU_CSR_FS; + fcr31 |= value & (FPU_CSR_ALL_E | FPU_CSR_RM); + break; + + case FPCREG_FEXR: + if (!cpu_has_mips_r) + break; + pr_debug("%p gpr[%d]->exr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + fcr31 &= ~(FPU_CSR_ALL_X | FPU_CSR_ALL_S); + fcr31 |= value & (FPU_CSR_ALL_X | FPU_CSR_ALL_S); + break; + + case FPCREG_FCCR: + if (!cpu_has_mips_r) + break; + pr_debug("%p gpr[%d]->ccr=%08x\n", + (void *)xcp->cp0_epc, MIPSInst_RT(ir), value); + fcr31 &= ~(FPU_CSR_CONDX | FPU_CSR_COND); + fcr31 |= (value << (FPU_CSR_COND_S - MIPS_FCCR_COND0_S)) & + FPU_CSR_COND; + fcr31 |= (value << (FPU_CSR_COND1_S - MIPS_FCCR_COND1_S)) & + FPU_CSR_CONDX; + break; + + default: + break; + } + + ctx->fcr31 = fcr31; +} + +/* + * Emulate the single floating point instruction pointed at by EPC. + * Two instructions if the instruction is in a branch delay slot. + */ + +static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_struct *ctx, + struct mm_decoded_insn dec_insn, void *__user *fault_addr) +{ + unsigned long contpc = xcp->cp0_epc + dec_insn.pc_inc; + unsigned int cond, cbit; + mips_instruction ir; + int likely, pc_inc; + u32 __user *wva; + u64 __user *dva; + u32 wval; + u64 dval; + int sig; + + /* + * These are giving gcc a gentle hint about what to expect in + * dec_inst in order to do better optimization. + */ + if (!cpu_has_mmips && dec_insn.micro_mips_mode) + unreachable(); + + /* XXX NEC Vr54xx bug workaround */ + if (delay_slot(xcp)) { + if (dec_insn.micro_mips_mode) { + if (!mm_isBranchInstr(xcp, dec_insn, &contpc)) + clear_delay_slot(xcp); + } else { + if (!isBranchInstr(xcp, dec_insn, &contpc)) + clear_delay_slot(xcp); + } + } + + if (delay_slot(xcp)) { + /* + * The instruction to be emulated is in a branch delay slot + * which means that we have to emulate the branch instruction + * BEFORE we do the cop1 instruction. + * + * This branch could be a COP1 branch, but in that case we + * would have had a trap for that instruction, and would not + * come through this route. + * + * Linux MIPS branch emulator operates on context, updating the + * cp0_epc. + */ + ir = dec_insn.next_insn; /* process delay slot instr */ + pc_inc = dec_insn.next_pc_inc; + } else { + ir = dec_insn.insn; /* process current instr */ + pc_inc = dec_insn.pc_inc; + } + + /* + * Since microMIPS FPU instructios are a subset of MIPS32 FPU + * instructions, we want to convert microMIPS FPU instructions + * into MIPS32 instructions so that we could reuse all of the + * FPU emulation code. + * + * NOTE: We cannot do this for branch instructions since they + * are not a subset. Example: Cannot emulate a 16-bit + * aligned target address with a MIPS32 instruction. + */ + if (dec_insn.micro_mips_mode) { + /* + * If next instruction is a 16-bit instruction, then it + * it cannot be a FPU instruction. This could happen + * since we can be called for non-FPU instructions. + */ + if ((pc_inc == 2) || + (microMIPS32_to_MIPS32((union mips_instruction *)&ir) + == SIGILL)) + return SIGILL; + } + +emul: + perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, xcp, 0); + MIPS_FPU_EMU_INC_STATS(emulated); + switch (MIPSInst_OPCODE(ir)) { + case ldc1_op: + dva = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] + + MIPSInst_SIMM(ir)); + MIPS_FPU_EMU_INC_STATS(loads); + + if (!access_ok(VERIFY_READ, dva, sizeof(u64))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = dva; + return SIGBUS; + } + if (__get_user(dval, dva)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = dva; + return SIGSEGV; + } + DITOREG(dval, MIPSInst_RT(ir)); + break; + + case sdc1_op: + dva = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] + + MIPSInst_SIMM(ir)); + MIPS_FPU_EMU_INC_STATS(stores); + DIFROMREG(dval, MIPSInst_RT(ir)); + if (!access_ok(VERIFY_WRITE, dva, sizeof(u64))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = dva; + return SIGBUS; + } + if (__put_user(dval, dva)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = dva; + return SIGSEGV; + } + break; + + case lwc1_op: + wva = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] + + MIPSInst_SIMM(ir)); + MIPS_FPU_EMU_INC_STATS(loads); + if (!access_ok(VERIFY_READ, wva, sizeof(u32))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = wva; + return SIGBUS; + } + if (__get_user(wval, wva)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = wva; + return SIGSEGV; + } + SITOREG(wval, MIPSInst_RT(ir)); + break; + + case swc1_op: + wva = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] + + MIPSInst_SIMM(ir)); + MIPS_FPU_EMU_INC_STATS(stores); + SIFROMREG(wval, MIPSInst_RT(ir)); + if (!access_ok(VERIFY_WRITE, wva, sizeof(u32))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = wva; + return SIGBUS; + } + if (__put_user(wval, wva)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = wva; + return SIGSEGV; + } + break; + + case cop1_op: + switch (MIPSInst_RS(ir)) { + case dmfc_op: + if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + return SIGILL; + + /* copregister fs -> gpr[rt] */ + if (MIPSInst_RT(ir) != 0) { + DIFROMREG(xcp->regs[MIPSInst_RT(ir)], + MIPSInst_RD(ir)); + } + break; + + case dmtc_op: + if (!cpu_has_mips_3_4_5 && !cpu_has_mips64) + return SIGILL; + + /* copregister fs <- rt */ + DITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir)); + break; + + case mfhc_op: + if (!cpu_has_mips_r2) + goto sigill; + + /* copregister rd -> gpr[rt] */ + if (MIPSInst_RT(ir) != 0) { + SIFROMHREG(xcp->regs[MIPSInst_RT(ir)], + MIPSInst_RD(ir)); + } + break; + + case mthc_op: + if (!cpu_has_mips_r2) + goto sigill; + + /* copregister rd <- gpr[rt] */ + SITOHREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir)); + break; + + case mfc_op: + /* copregister rd -> gpr[rt] */ + if (MIPSInst_RT(ir) != 0) { + SIFROMREG(xcp->regs[MIPSInst_RT(ir)], + MIPSInst_RD(ir)); + } + break; + + case mtc_op: + /* copregister rd <- rt */ + SITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir)); + break; + + case cfc_op: + /* cop control register rd -> gpr[rt] */ + cop1_cfc(xcp, ctx, ir); + break; + + case ctc_op: + /* copregister rd <- rt */ + cop1_ctc(xcp, ctx, ir); + if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) { + return SIGFPE; + } + break; + + case bc_op: + if (delay_slot(xcp)) + return SIGILL; + + if (cpu_has_mips_4_5_r) + cbit = fpucondbit[MIPSInst_RT(ir) >> 2]; + else + cbit = FPU_CSR_COND; + cond = ctx->fcr31 & cbit; + + likely = 0; + switch (MIPSInst_RT(ir) & 3) { + case bcfl_op: + if (cpu_has_mips_2_3_4_5_r) + likely = 1; + /* Fall through */ + case bcf_op: + cond = !cond; + break; + case bctl_op: + if (cpu_has_mips_2_3_4_5_r) + likely = 1; + /* Fall through */ + case bct_op: + break; + } + + set_delay_slot(xcp); + if (cond) { + /* + * Branch taken: emulate dslot instruction + */ + unsigned long bcpc; + + /* + * Remember EPC at the branch to point back + * at so that any delay-slot instruction + * signal is not silently ignored. + */ + bcpc = xcp->cp0_epc; + xcp->cp0_epc += dec_insn.pc_inc; + + contpc = MIPSInst_SIMM(ir); + ir = dec_insn.next_insn; + if (dec_insn.micro_mips_mode) { + contpc = (xcp->cp0_epc + (contpc << 1)); + + /* If 16-bit instruction, not FPU. */ + if ((dec_insn.next_pc_inc == 2) || + (microMIPS32_to_MIPS32((union mips_instruction *)&ir) == SIGILL)) { + + /* + * Since this instruction will + * be put on the stack with + * 32-bit words, get around + * this problem by putting a + * NOP16 as the second one. + */ + if (dec_insn.next_pc_inc == 2) + ir = (ir & (~0xffff)) | MM_NOP16; + + /* + * Single step the non-CP1 + * instruction in the dslot. + */ + sig = mips_dsemul(xcp, ir, + contpc); + if (sig) + xcp->cp0_epc = bcpc; + /* + * SIGILL forces out of + * the emulation loop. + */ + return sig ? sig : SIGILL; + } + } else + contpc = (xcp->cp0_epc + (contpc << 2)); + + switch (MIPSInst_OPCODE(ir)) { + case lwc1_op: + case swc1_op: + goto emul; + + case ldc1_op: + case sdc1_op: + if (cpu_has_mips_2_3_4_5_r) + goto emul; + + goto bc_sigill; + + case cop1_op: + goto emul; + + case cop1x_op: + if (cpu_has_mips_4_5_64_r2_r6) + /* its one of ours */ + goto emul; + + goto bc_sigill; + + case spec_op: + switch (MIPSInst_FUNC(ir)) { + case movc_op: + if (cpu_has_mips_4_5_r) + goto emul; + + goto bc_sigill; + } + break; + + bc_sigill: + xcp->cp0_epc = bcpc; + return SIGILL; + } + + /* + * Single step the non-cp1 + * instruction in the dslot + */ + sig = mips_dsemul(xcp, ir, contpc); + if (sig) + xcp->cp0_epc = bcpc; + /* SIGILL forces out of the emulation loop. */ + return sig ? sig : SIGILL; + } else if (likely) { /* branch not taken */ + /* + * branch likely nullifies + * dslot if not taken + */ + xcp->cp0_epc += dec_insn.pc_inc; + contpc += dec_insn.pc_inc; + /* + * else continue & execute + * dslot as normal insn + */ + } + break; + + default: + if (!(MIPSInst_RS(ir) & 0x10)) + return SIGILL; + + /* a real fpu computation instruction */ + if ((sig = fpu_emu(xcp, ctx, ir))) + return sig; + } + break; + + case cop1x_op: + if (!cpu_has_mips_4_5_64_r2_r6) + return SIGILL; + + sig = fpux_emu(xcp, ctx, ir, fault_addr); + if (sig) + return sig; + break; + + case spec_op: + if (!cpu_has_mips_4_5_r) + return SIGILL; + + if (MIPSInst_FUNC(ir) != movc_op) + return SIGILL; + cond = fpucondbit[MIPSInst_RT(ir) >> 2]; + if (((ctx->fcr31 & cond) != 0) == ((MIPSInst_RT(ir) & 1) != 0)) + xcp->regs[MIPSInst_RD(ir)] = + xcp->regs[MIPSInst_RS(ir)]; + break; + default: +sigill: + return SIGILL; + } + + /* we did it !! */ + xcp->cp0_epc = contpc; + clear_delay_slot(xcp); + + return 0; +} + +/* + * Conversion table from MIPS compare ops 48-63 + * cond = ieee754dp_cmp(x,y,IEEE754_UN,sig); + */ +static const unsigned char cmptab[8] = { + 0, /* cmp_0 (sig) cmp_sf */ + IEEE754_CUN, /* cmp_un (sig) cmp_ngle */ + IEEE754_CEQ, /* cmp_eq (sig) cmp_seq */ + IEEE754_CEQ | IEEE754_CUN, /* cmp_ueq (sig) cmp_ngl */ + IEEE754_CLT, /* cmp_olt (sig) cmp_lt */ + IEEE754_CLT | IEEE754_CUN, /* cmp_ult (sig) cmp_nge */ + IEEE754_CLT | IEEE754_CEQ, /* cmp_ole (sig) cmp_le */ + IEEE754_CLT | IEEE754_CEQ | IEEE754_CUN, /* cmp_ule (sig) cmp_ngt */ +}; + + +/* + * Additional MIPS4 instructions + */ + +#define DEF3OP(name, p, f1, f2, f3) \ +static union ieee754##p fpemu_##p##_##name(union ieee754##p r, \ + union ieee754##p s, union ieee754##p t) \ +{ \ + struct _ieee754_csr ieee754_csr_save; \ + s = f1(s, t); \ + ieee754_csr_save = ieee754_csr; \ + s = f2(s, r); \ + ieee754_csr_save.cx |= ieee754_csr.cx; \ + ieee754_csr_save.sx |= ieee754_csr.sx; \ + s = f3(s); \ + ieee754_csr.cx |= ieee754_csr_save.cx; \ + ieee754_csr.sx |= ieee754_csr_save.sx; \ + return s; \ +} + +static union ieee754dp fpemu_dp_recip(union ieee754dp d) +{ + return ieee754dp_div(ieee754dp_one(0), d); +} + +static union ieee754dp fpemu_dp_rsqrt(union ieee754dp d) +{ + return ieee754dp_div(ieee754dp_one(0), ieee754dp_sqrt(d)); +} + +static union ieee754sp fpemu_sp_recip(union ieee754sp s) +{ + return ieee754sp_div(ieee754sp_one(0), s); +} + +static union ieee754sp fpemu_sp_rsqrt(union ieee754sp s) +{ + return ieee754sp_div(ieee754sp_one(0), ieee754sp_sqrt(s)); +} + +DEF3OP(madd, sp, ieee754sp_mul, ieee754sp_add, ); +DEF3OP(msub, sp, ieee754sp_mul, ieee754sp_sub, ); +DEF3OP(nmadd, sp, ieee754sp_mul, ieee754sp_add, ieee754sp_neg); +DEF3OP(nmsub, sp, ieee754sp_mul, ieee754sp_sub, ieee754sp_neg); +DEF3OP(madd, dp, ieee754dp_mul, ieee754dp_add, ); +DEF3OP(msub, dp, ieee754dp_mul, ieee754dp_sub, ); +DEF3OP(nmadd, dp, ieee754dp_mul, ieee754dp_add, ieee754dp_neg); +DEF3OP(nmsub, dp, ieee754dp_mul, ieee754dp_sub, ieee754dp_neg); + +static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx, + mips_instruction ir, void *__user *fault_addr) +{ + unsigned rcsr = 0; /* resulting csr */ + + MIPS_FPU_EMU_INC_STATS(cp1xops); + + switch (MIPSInst_FMA_FFMT(ir)) { + case s_fmt:{ /* 0 */ + + union ieee754sp(*handler) (union ieee754sp, union ieee754sp, union ieee754sp); + union ieee754sp fd, fr, fs, ft; + u32 __user *va; + u32 val; + + switch (MIPSInst_FUNC(ir)) { + case lwxc1_op: + va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] + + xcp->regs[MIPSInst_FT(ir)]); + + MIPS_FPU_EMU_INC_STATS(loads); + if (!access_ok(VERIFY_READ, va, sizeof(u32))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGBUS; + } + if (__get_user(val, va)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGSEGV; + } + SITOREG(val, MIPSInst_FD(ir)); + break; + + case swxc1_op: + va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] + + xcp->regs[MIPSInst_FT(ir)]); + + MIPS_FPU_EMU_INC_STATS(stores); + + SIFROMREG(val, MIPSInst_FS(ir)); + if (!access_ok(VERIFY_WRITE, va, sizeof(u32))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGBUS; + } + if (put_user(val, va)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGSEGV; + } + break; + + case madd_s_op: + handler = fpemu_sp_madd; + goto scoptop; + case msub_s_op: + handler = fpemu_sp_msub; + goto scoptop; + case nmadd_s_op: + handler = fpemu_sp_nmadd; + goto scoptop; + case nmsub_s_op: + handler = fpemu_sp_nmsub; + goto scoptop; + + scoptop: + SPFROMREG(fr, MIPSInst_FR(ir)); + SPFROMREG(fs, MIPSInst_FS(ir)); + SPFROMREG(ft, MIPSInst_FT(ir)); + fd = (*handler) (fr, fs, ft); + SPTOREG(fd, MIPSInst_FD(ir)); + + copcsr: + if (ieee754_cxtest(IEEE754_INEXACT)) { + MIPS_FPU_EMU_INC_STATS(ieee754_inexact); + rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S; + } + if (ieee754_cxtest(IEEE754_UNDERFLOW)) { + MIPS_FPU_EMU_INC_STATS(ieee754_underflow); + rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S; + } + if (ieee754_cxtest(IEEE754_OVERFLOW)) { + MIPS_FPU_EMU_INC_STATS(ieee754_overflow); + rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S; + } + if (ieee754_cxtest(IEEE754_INVALID_OPERATION)) { + MIPS_FPU_EMU_INC_STATS(ieee754_invalidop); + rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S; + } + + ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr; + if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) { + /*printk ("SIGFPE: FPU csr = %08x\n", + ctx->fcr31); */ + return SIGFPE; + } + + break; + + default: + return SIGILL; + } + break; + } + + case d_fmt:{ /* 1 */ + union ieee754dp(*handler) (union ieee754dp, union ieee754dp, union ieee754dp); + union ieee754dp fd, fr, fs, ft; + u64 __user *va; + u64 val; + + switch (MIPSInst_FUNC(ir)) { + case ldxc1_op: + va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] + + xcp->regs[MIPSInst_FT(ir)]); + + MIPS_FPU_EMU_INC_STATS(loads); + if (!access_ok(VERIFY_READ, va, sizeof(u64))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGBUS; + } + if (__get_user(val, va)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGSEGV; + } + DITOREG(val, MIPSInst_FD(ir)); + break; + + case sdxc1_op: + va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] + + xcp->regs[MIPSInst_FT(ir)]); + + MIPS_FPU_EMU_INC_STATS(stores); + DIFROMREG(val, MIPSInst_FS(ir)); + if (!access_ok(VERIFY_WRITE, va, sizeof(u64))) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGBUS; + } + if (__put_user(val, va)) { + MIPS_FPU_EMU_INC_STATS(errors); + *fault_addr = va; + return SIGSEGV; + } + break; + + case madd_d_op: + handler = fpemu_dp_madd; + goto dcoptop; + case msub_d_op: + handler = fpemu_dp_msub; + goto dcoptop; + case nmadd_d_op: + handler = fpemu_dp_nmadd; + goto dcoptop; + case nmsub_d_op: + handler = fpemu_dp_nmsub; + goto dcoptop; + + dcoptop: + DPFROMREG(fr, MIPSInst_FR(ir)); + DPFROMREG(fs, MIPSInst_FS(ir)); + DPFROMREG(ft, MIPSInst_FT(ir)); + fd = (*handler) (fr, fs, ft); + DPTOREG(fd, MIPSInst_FD(ir)); + goto copcsr; + + default: + return SIGILL; + } + break; + } + + case 0x3: + if (MIPSInst_FUNC(ir) != pfetch_op) + return SIGILL; + + /* ignore prefx operation */ + break; + + default: + return SIGILL; + } + + return 0; +} + + + +/* + * Emulate a single COP1 arithmetic instruction. + */ +static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx, + mips_instruction ir) +{ + int rfmt; /* resulting format */ + unsigned rcsr = 0; /* resulting csr */ + unsigned int oldrm; + unsigned int cbit; + unsigned cond; + union { + union ieee754dp d; + union ieee754sp s; + int w; + s64 l; + } rv; /* resulting value */ + u64 bits; + + MIPS_FPU_EMU_INC_STATS(cp1ops); + switch (rfmt = (MIPSInst_FFMT(ir) & 0xf)) { + case s_fmt: { /* 0 */ + union { + union ieee754sp(*b) (union ieee754sp, union ieee754sp); + union ieee754sp(*u) (union ieee754sp); + } handler; + union ieee754sp fs, ft; + + switch (MIPSInst_FUNC(ir)) { + /* binary ops */ + case fadd_op: + handler.b = ieee754sp_add; + goto scopbop; + case fsub_op: + handler.b = ieee754sp_sub; + goto scopbop; + case fmul_op: + handler.b = ieee754sp_mul; + goto scopbop; + case fdiv_op: + handler.b = ieee754sp_div; + goto scopbop; + + /* unary ops */ + case fsqrt_op: + if (!cpu_has_mips_2_3_4_5_r) + return SIGILL; + + handler.u = ieee754sp_sqrt; + goto scopuop; + + /* + * Note that on some MIPS IV implementations such as the + * R5000 and R8000 the FSQRT and FRECIP instructions do not + * achieve full IEEE-754 accuracy - however this emulator does. + */ + case frsqrt_op: + if (!cpu_has_mips_4_5_64_r2_r6) + return SIGILL; + + handler.u = fpemu_sp_rsqrt; + goto scopuop; + + case frecip_op: + if (!cpu_has_mips_4_5_64_r2_r6) + return SIGILL; + + handler.u = fpemu_sp_recip; + goto scopuop; + + case fmovc_op: + if (!cpu_has_mips_4_5_r) + return SIGILL; + + cond = fpucondbit[MIPSInst_FT(ir) >> 2]; + if (((ctx->fcr31 & cond) != 0) != + ((MIPSInst_FT(ir) & 1) != 0)) + return 0; + SPFROMREG(rv.s, MIPSInst_FS(ir)); + break; + + case fmovz_op: + if (!cpu_has_mips_4_5_r) + return SIGILL; + + if (xcp->regs[MIPSInst_FT(ir)] != 0) + return 0; + SPFROMREG(rv.s, MIPSInst_FS(ir)); + break; + + case fmovn_op: + if (!cpu_has_mips_4_5_r) + return SIGILL; + + if (xcp->regs[MIPSInst_FT(ir)] == 0) + return 0; + SPFROMREG(rv.s, MIPSInst_FS(ir)); + break; + + case fabs_op: + handler.u = ieee754sp_abs; + goto scopuop; + + case fneg_op: + handler.u = ieee754sp_neg; + goto scopuop; + + case fmov_op: + /* an easy one */ + SPFROMREG(rv.s, MIPSInst_FS(ir)); + goto copcsr; + + /* binary op on handler */ +scopbop: + SPFROMREG(fs, MIPSInst_FS(ir)); + SPFROMREG(ft, MIPSInst_FT(ir)); + + rv.s = (*handler.b) (fs, ft); + goto copcsr; +scopuop: + SPFROMREG(fs, MIPSInst_FS(ir)); + rv.s = (*handler.u) (fs); + goto copcsr; +copcsr: + if (ieee754_cxtest(IEEE754_INEXACT)) { + MIPS_FPU_EMU_INC_STATS(ieee754_inexact); + rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S; + } + if (ieee754_cxtest(IEEE754_UNDERFLOW)) { + MIPS_FPU_EMU_INC_STATS(ieee754_underflow); + rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S; + } + if (ieee754_cxtest(IEEE754_OVERFLOW)) { + MIPS_FPU_EMU_INC_STATS(ieee754_overflow); + rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S; + } + if (ieee754_cxtest(IEEE754_ZERO_DIVIDE)) { + MIPS_FPU_EMU_INC_STATS(ieee754_zerodiv); + rcsr |= FPU_CSR_DIV_X | FPU_CSR_DIV_S; + } + if (ieee754_cxtest(IEEE754_INVALID_OPERATION)) { + MIPS_FPU_EMU_INC_STATS(ieee754_invalidop); + rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S; + } + break; + + /* unary conv ops */ + case fcvts_op: + return SIGILL; /* not defined */ + + case fcvtd_op: + SPFROMREG(fs, MIPSInst_FS(ir)); + rv.d = ieee754dp_fsp(fs); + rfmt = d_fmt; + goto copcsr; + + case fcvtw_op: + SPFROMREG(fs, MIPSInst_FS(ir)); + rv.w = ieee754sp_tint(fs); + rfmt = w_fmt; + goto copcsr; + + case fround_op: + case ftrunc_op: + case fceil_op: + case ffloor_op: + if (!cpu_has_mips_2_3_4_5_r) + return SIGILL; + + oldrm = ieee754_csr.rm; + SPFROMREG(fs, MIPSInst_FS(ir)); + ieee754_csr.rm = MIPSInst_FUNC(ir); + rv.w = ieee754sp_tint(fs); + ieee754_csr.rm = oldrm; + rfmt = w_fmt; + goto copcsr; + + case fcvtl_op: + if (!cpu_has_mips_3_4_5_64_r2_r6) + return SIGILL; + + SPFROMREG(fs, MIPSInst_FS(ir)); + rv.l = ieee754sp_tlong(fs); + rfmt = l_fmt; + goto copcsr; + + case froundl_op: + case ftruncl_op: + case fceill_op: + case ffloorl_op: + if (!cpu_has_mips_3_4_5_64_r2_r6) + return SIGILL; + + oldrm = ieee754_csr.rm; + SPFROMREG(fs, MIPSInst_FS(ir)); + ieee754_csr.rm = MIPSInst_FUNC(ir); + rv.l = ieee754sp_tlong(fs); + ieee754_csr.rm = oldrm; + rfmt = l_fmt; + goto copcsr; + + default: + if (MIPSInst_FUNC(ir) >= fcmp_op) { + unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op; + union ieee754sp fs, ft; + + SPFROMREG(fs, MIPSInst_FS(ir)); + SPFROMREG(ft, MIPSInst_FT(ir)); + rv.w = ieee754sp_cmp(fs, ft, + cmptab[cmpop & 0x7], cmpop & 0x8); + rfmt = -1; + if ((cmpop & 0x8) && ieee754_cxtest + (IEEE754_INVALID_OPERATION)) + rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S; + else + goto copcsr; + + } else + return SIGILL; + break; + } + break; + } + + case d_fmt: { + union ieee754dp fs, ft; + union { + union ieee754dp(*b) (union ieee754dp, union ieee754dp); + union ieee754dp(*u) (union ieee754dp); + } handler; + + switch (MIPSInst_FUNC(ir)) { + /* binary ops */ + case fadd_op: + handler.b = ieee754dp_add; + goto dcopbop; + case fsub_op: + handler.b = ieee754dp_sub; + goto dcopbop; + case fmul_op: + handler.b = ieee754dp_mul; + goto dcopbop; + case fdiv_op: + handler.b = ieee754dp_div; + goto dcopbop; + + /* unary ops */ + case fsqrt_op: + if (!cpu_has_mips_2_3_4_5_r) + return SIGILL; + + handler.u = ieee754dp_sqrt; + goto dcopuop; + /* + * Note that on some MIPS IV implementations such as the + * R5000 and R8000 the FSQRT and FRECIP instructions do not + * achieve full IEEE-754 accuracy - however this emulator does. + */ + case frsqrt_op: + if (!cpu_has_mips_4_5_64_r2_r6) + return SIGILL; + + handler.u = fpemu_dp_rsqrt; + goto dcopuop; + case frecip_op: + if (!cpu_has_mips_4_5_64_r2_r6) + return SIGILL; + + handler.u = fpemu_dp_recip; + goto dcopuop; + case fmovc_op: + if (!cpu_has_mips_4_5_r) + return SIGILL; + + cond = fpucondbit[MIPSInst_FT(ir) >> 2]; + if (((ctx->fcr31 & cond) != 0) != + ((MIPSInst_FT(ir) & 1) != 0)) + return 0; + DPFROMREG(rv.d, MIPSInst_FS(ir)); + break; + case fmovz_op: + if (!cpu_has_mips_4_5_r) + return SIGILL; + + if (xcp->regs[MIPSInst_FT(ir)] != 0) + return 0; + DPFROMREG(rv.d, MIPSInst_FS(ir)); + break; + case fmovn_op: + if (!cpu_has_mips_4_5_r) + return SIGILL; + + if (xcp->regs[MIPSInst_FT(ir)] == 0) + return 0; + DPFROMREG(rv.d, MIPSInst_FS(ir)); + break; + case fabs_op: + handler.u = ieee754dp_abs; + goto dcopuop; + + case fneg_op: + handler.u = ieee754dp_neg; + goto dcopuop; + + case fmov_op: + /* an easy one */ + DPFROMREG(rv.d, MIPSInst_FS(ir)); + goto copcsr; + + /* binary op on handler */ +dcopbop: + DPFROMREG(fs, MIPSInst_FS(ir)); + DPFROMREG(ft, MIPSInst_FT(ir)); + + rv.d = (*handler.b) (fs, ft); + goto copcsr; +dcopuop: + DPFROMREG(fs, MIPSInst_FS(ir)); + rv.d = (*handler.u) (fs); + goto copcsr; + + /* + * unary conv ops + */ + case fcvts_op: + DPFROMREG(fs, MIPSInst_FS(ir)); + rv.s = ieee754sp_fdp(fs); + rfmt = s_fmt; + goto copcsr; + + case fcvtd_op: + return SIGILL; /* not defined */ + + case fcvtw_op: + DPFROMREG(fs, MIPSInst_FS(ir)); + rv.w = ieee754dp_tint(fs); /* wrong */ + rfmt = w_fmt; + goto copcsr; + + case fround_op: + case ftrunc_op: + case fceil_op: + case ffloor_op: + if (!cpu_has_mips_2_3_4_5_r) + return SIGILL; + + oldrm = ieee754_csr.rm; + DPFROMREG(fs, MIPSInst_FS(ir)); + ieee754_csr.rm = MIPSInst_FUNC(ir); + rv.w = ieee754dp_tint(fs); + ieee754_csr.rm = oldrm; + rfmt = w_fmt; + goto copcsr; + + case fcvtl_op: + if (!cpu_has_mips_3_4_5_64_r2_r6) + return SIGILL; + + DPFROMREG(fs, MIPSInst_FS(ir)); + rv.l = ieee754dp_tlong(fs); + rfmt = l_fmt; + goto copcsr; + + case froundl_op: + case ftruncl_op: + case fceill_op: + case ffloorl_op: + if (!cpu_has_mips_3_4_5_64_r2_r6) + return SIGILL; + + oldrm = ieee754_csr.rm; + DPFROMREG(fs, MIPSInst_FS(ir)); + ieee754_csr.rm = MIPSInst_FUNC(ir); + rv.l = ieee754dp_tlong(fs); + ieee754_csr.rm = oldrm; + rfmt = l_fmt; + goto copcsr; + + default: + if (MIPSInst_FUNC(ir) >= fcmp_op) { + unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op; + union ieee754dp fs, ft; + + DPFROMREG(fs, MIPSInst_FS(ir)); + DPFROMREG(ft, MIPSInst_FT(ir)); + rv.w = ieee754dp_cmp(fs, ft, + cmptab[cmpop & 0x7], cmpop & 0x8); + rfmt = -1; + if ((cmpop & 0x8) + && + ieee754_cxtest + (IEEE754_INVALID_OPERATION)) + rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S; + else + goto copcsr; + + } + else { + return SIGILL; + } + break; + } + break; + + case w_fmt: + switch (MIPSInst_FUNC(ir)) { + case fcvts_op: + /* convert word to single precision real */ + SPFROMREG(fs, MIPSInst_FS(ir)); + rv.s = ieee754sp_fint(fs.bits); + rfmt = s_fmt; + goto copcsr; + case fcvtd_op: + /* convert word to double precision real */ + SPFROMREG(fs, MIPSInst_FS(ir)); + rv.d = ieee754dp_fint(fs.bits); + rfmt = d_fmt; + goto copcsr; + default: + return SIGILL; + } + break; + } + + case l_fmt: + + if (!cpu_has_mips_3_4_5_64_r2_r6) + return SIGILL; + + DIFROMREG(bits, MIPSInst_FS(ir)); + + switch (MIPSInst_FUNC(ir)) { + case fcvts_op: + /* convert long to single precision real */ + rv.s = ieee754sp_flong(bits); + rfmt = s_fmt; + goto copcsr; + case fcvtd_op: + /* convert long to double precision real */ + rv.d = ieee754dp_flong(bits); + rfmt = d_fmt; + goto copcsr; + default: + return SIGILL; + } + break; + + default: + return SIGILL; + } + + /* + * Update the fpu CSR register for this operation. + * If an exception is required, generate a tidy SIGFPE exception, + * without updating the result register. + * Note: cause exception bits do not accumulate, they are rewritten + * for each op; only the flag/sticky bits accumulate. + */ + ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr; + if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) { + /*printk ("SIGFPE: FPU csr = %08x\n",ctx->fcr31); */ + return SIGFPE; + } + + /* + * Now we can safely write the result back to the register file. + */ + switch (rfmt) { + case -1: + + if (cpu_has_mips_4_5_r) + cbit = fpucondbit[MIPSInst_FD(ir) >> 2]; + else + cbit = FPU_CSR_COND; + if (rv.w) + ctx->fcr31 |= cbit; + else + ctx->fcr31 &= ~cbit; + break; + + case d_fmt: + DPTOREG(rv.d, MIPSInst_FD(ir)); + break; + case s_fmt: + SPTOREG(rv.s, MIPSInst_FD(ir)); + break; + case w_fmt: + SITOREG(rv.w, MIPSInst_FD(ir)); + break; + case l_fmt: + if (!cpu_has_mips_3_4_5_64_r2_r6) + return SIGILL; + + DITOREG(rv.l, MIPSInst_FD(ir)); + break; + default: + return SIGILL; + } + + return 0; +} + +int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx, + int has_fpu, void *__user *fault_addr) +{ + unsigned long oldepc, prevepc; + struct mm_decoded_insn dec_insn; + u16 instr[4]; + u16 *instr_ptr; + int sig = 0; + + oldepc = xcp->cp0_epc; + do { + prevepc = xcp->cp0_epc; + + if (get_isa16_mode(prevepc) && cpu_has_mmips) { + /* + * Get next 2 microMIPS instructions and convert them + * into 32-bit instructions. + */ + if ((get_user(instr[0], (u16 __user *)msk_isa16_mode(xcp->cp0_epc))) || + (get_user(instr[1], (u16 __user *)msk_isa16_mode(xcp->cp0_epc + 2))) || + (get_user(instr[2], (u16 __user *)msk_isa16_mode(xcp->cp0_epc + 4))) || + (get_user(instr[3], (u16 __user *)msk_isa16_mode(xcp->cp0_epc + 6)))) { + MIPS_FPU_EMU_INC_STATS(errors); + return SIGBUS; + } + instr_ptr = instr; + + /* Get first instruction. */ + if (mm_insn_16bit(*instr_ptr)) { + /* Duplicate the half-word. */ + dec_insn.insn = (*instr_ptr << 16) | + (*instr_ptr); + /* 16-bit instruction. */ + dec_insn.pc_inc = 2; + instr_ptr += 1; + } else { + dec_insn.insn = (*instr_ptr << 16) | + *(instr_ptr+1); + /* 32-bit instruction. */ + dec_insn.pc_inc = 4; + instr_ptr += 2; + } + /* Get second instruction. */ + if (mm_insn_16bit(*instr_ptr)) { + /* Duplicate the half-word. */ + dec_insn.next_insn = (*instr_ptr << 16) | + (*instr_ptr); + /* 16-bit instruction. */ + dec_insn.next_pc_inc = 2; + } else { + dec_insn.next_insn = (*instr_ptr << 16) | + *(instr_ptr+1); + /* 32-bit instruction. */ + dec_insn.next_pc_inc = 4; + } + dec_insn.micro_mips_mode = 1; + } else { + if ((get_user(dec_insn.insn, + (mips_instruction __user *) xcp->cp0_epc)) || + (get_user(dec_insn.next_insn, + (mips_instruction __user *)(xcp->cp0_epc+4)))) { + MIPS_FPU_EMU_INC_STATS(errors); + return SIGBUS; + } + dec_insn.pc_inc = 4; + dec_insn.next_pc_inc = 4; + dec_insn.micro_mips_mode = 0; + } + + if ((dec_insn.insn == 0) || + ((dec_insn.pc_inc == 2) && + ((dec_insn.insn & 0xffff) == MM_NOP16))) + xcp->cp0_epc += dec_insn.pc_inc; /* Skip NOPs */ + else { + /* + * The 'ieee754_csr' is an alias of ctx->fcr31. + * No need to copy ctx->fcr31 to ieee754_csr. + */ + sig = cop1Emulate(xcp, ctx, dec_insn, fault_addr); + } + + if (has_fpu) + break; + if (sig) + break; + + cond_resched(); + } while (xcp->cp0_epc > prevepc); + + /* SIGILL indicates a non-fpu instruction */ + if (sig == SIGILL && xcp->cp0_epc != oldepc) + /* but if EPC has advanced, then ignore it */ + sig = 0; + + return sig; +} |