Merge pull request #4046 from balanceTWK/riscv_fpu_k210_20201120

[libcpu/risc-v][K210] add FPU support

10 files changed, 237 insertions, 35 deletions

diff --git a/bsp/k210/.config b/bsp/k210/.config
index 705dc78652..4d6db95162 100644
--- a/bsp/k210/.config
+++ b/bsp/k210/.config
@@ -70,6 +70,8 @@ CONFIG_RT_VER_NUM=0x40003
 CONFIG_ARCH_CPU_64BIT=y
 # CONFIG_RT_USING_CPU_FFS is not set
 CONFIG_ARCH_RISCV=y
+CONFIG_ARCH_RISCV_FPU=y
+CONFIG_ARCH_RISCV_FPU_S=y
 CONFIG_ARCH_RISCV64=y
 # CONFIG_ARCH_CPU_STACK_GROWS_UPWARD is not set
 
@@ -150,8 +152,10 @@ CONFIG_RT_SERIAL_RB_BUFSZ=64
 # CONFIG_RT_USING_HWTIMER is not set
 # CONFIG_RT_USING_CPUTIME is not set
 # CONFIG_RT_USING_I2C is not set
+# CONFIG_RT_USING_PHY is not set
 CONFIG_RT_USING_PIN=y
 # CONFIG_RT_USING_ADC is not set
+# CONFIG_RT_USING_DAC is not set
 # CONFIG_RT_USING_PWM is not set
 # CONFIG_RT_USING_MTD_NOR is not set
 # CONFIG_RT_USING_MTD_NAND is not set
@@ -192,6 +196,7 @@ CONFIG_RT_USING_LIBC=y
 CONFIG_RT_USING_POSIX=y
 # CONFIG_RT_USING_POSIX_MMAP is not set
 # CONFIG_RT_USING_POSIX_TERMIOS is not set
+# CONFIG_RT_USING_POSIX_GETLINE is not set
 # CONFIG_RT_USING_POSIX_AIO is not set
 # CONFIG_RT_USING_MODULE is not set
 
@@ -262,7 +267,9 @@ CONFIG_ULOG_BACKEND_USING_CONSOLE=y
 #
 # IoT - internet of things
 #
+# CONFIG_PKG_USING_LORAWAN_DRIVER is not set
 # CONFIG_PKG_USING_PAHOMQTT is not set
+# CONFIG_PKG_USING_UMQTT is not set
 # CONFIG_PKG_USING_WEBCLIENT is not set
 # CONFIG_PKG_USING_WEBNET is not set
 # CONFIG_PKG_USING_MONGOOSE is not set
@@ -308,7 +315,7 @@ CONFIG_ULOG_BACKEND_USING_CONSOLE=y
 # CONFIG_PKG_USING_GAGENT_CLOUD is not set
 # CONFIG_PKG_USING_ALI_IOTKIT is not set
 # CONFIG_PKG_USING_AZURE is not set
-# CONFIG_PKG_USING_TENCENT_IOTHUB is not set
+# CONFIG_PKG_USING_TENCENT_IOT_EXPLORER is not set
 # CONFIG_PKG_USING_JIOT-C-SDK is not set
 # CONFIG_PKG_USING_UCLOUD_IOT_SDK is not set
 # CONFIG_PKG_USING_JOYLINK is not set
@@ -330,6 +337,9 @@ CONFIG_ULOG_BACKEND_USING_CONSOLE=y
 # CONFIG_PKG_USING_CAPNP is not set
 # CONFIG_PKG_USING_RT_CJSON_TOOLS is not set
 # CONFIG_PKG_USING_AGILE_TELNET is not set
+# CONFIG_PKG_USING_NMEALIB is not set
+# CONFIG_PKG_USING_AGILE_JSMN is not set
+# CONFIG_PKG_USING_PDULIB is not set
 
 #
 # security packages
@@ -338,6 +348,7 @@ CONFIG_ULOG_BACKEND_USING_CONSOLE=y
 # CONFIG_PKG_USING_libsodium is not set
 # CONFIG_PKG_USING_TINYCRYPT is not set
 # CONFIG_PKG_USING_TFM is not set
+# CONFIG_PKG_USING_YD_CRYPTO is not set
 
 #
 # language packages
@@ -372,7 +383,9 @@ CONFIG_ULOG_BACKEND_USING_CONSOLE=y
 # CONFIG_PKG_USING_CHINESE_FONT_LIBRARY is not set
 # CONFIG_PKG_USING_LUNAR_CALENDAR is not set
 # CONFIG_PKG_USING_BS8116A is not set
+# CONFIG_PKG_USING_GPS_RMC is not set
 # CONFIG_PKG_USING_URLENCODE is not set
+# CONFIG_PKG_USING_UMCN is not set
 
 #
 # system packages
@@ -396,6 +409,10 @@ CONFIG_ULOG_BACKEND_USING_CONSOLE=y
 # CONFIG_PKG_USING_SYSWATCH is not set
 # CONFIG_PKG_USING_SYS_LOAD_MONITOR is not set
 # CONFIG_PKG_USING_PLCCORE is not set
+# CONFIG_PKG_USING_RAMDISK is not set
+# CONFIG_PKG_USING_MININI is not set
+# CONFIG_PKG_USING_QBOOT is not set
+# CONFIG_PKG_USING_UCOSIII_WRAPPER is not set
 
 #
 # peripheral libraries and drivers
@@ -441,6 +458,7 @@ CONFIG_PKG_KENDRYTE_SDK_VERNUM=0x0055
 # CONFIG_PKG_USING_RPLIDAR is not set
 # CONFIG_PKG_USING_AS608 is not set
 # CONFIG_PKG_USING_RC522 is not set
+# CONFIG_PKG_USING_WS2812B is not set
 # CONFIG_PKG_USING_EMBARC_BSP is not set
 # CONFIG_PKG_USING_EXTERN_RTC_DRIVERS is not set
 # CONFIG_PKG_USING_MULTI_RTIMER is not set
@@ -450,6 +468,12 @@ CONFIG_PKG_KENDRYTE_SDK_VERNUM=0x0055
 # CONFIG_PKG_USING_PMS_SERIES is not set
 # CONFIG_PKG_USING_NUCLEI_SDK is not set
 # CONFIG_PKG_USING_CAN_YMODEM is not set
+# CONFIG_PKG_USING_LORA_RADIO_DRIVER is not set
+# CONFIG_PKG_USING_QLED is not set
+# CONFIG_PKG_USING_PAJ7620 is not set
+# CONFIG_PKG_USING_AGILE_CONSOLE is not set
+# CONFIG_PKG_USING_LD3320 is not set
+# CONFIG_PKG_USING_WK2124 is not set
 
 #
 # miscellaneous packages
@@ -486,6 +510,9 @@ CONFIG_PKG_KENDRYTE_SDK_VERNUM=0x0055
 # CONFIG_PKG_USING_VT100 is not set
 # CONFIG_PKG_USING_ULAPACK is not set
 # CONFIG_PKG_USING_UKAL is not set
+# CONFIG_PKG_USING_CRCLIB is not set
+# CONFIG_PKG_USING_THREES is not set
+# CONFIG_PKG_USING_2048 is not set
 CONFIG_BOARD_K210_EVB=y
 CONFIG_BSP_USING_UART_HS=y
 
diff --git a/bsp/k210/Kconfig b/bsp/k210/Kconfig
index 5aa1e03dab..61ba3631c0 100644
--- a/bsp/k210/Kconfig
+++ b/bsp/k210/Kconfig
@@ -21,6 +21,7 @@ source "$PKGS_DIR/Kconfig"
 config BOARD_K210_EVB
     bool
     select ARCH_RISCV64
+    select ARCH_RISCV_FPU_S
     select PKG_USING_KENDRYTE_SDK
     select RT_USING_COMPONENTS_INIT
     select RT_USING_USER_MAIN
diff --git a/bsp/k210/rtconfig.h b/bsp/k210/rtconfig.h
index 5f87d58a1d..4ac2b8937c 100644
--- a/bsp/k210/rtconfig.h
+++ b/bsp/k210/rtconfig.h
@@ -48,6 +48,8 @@
 #define RT_VER_NUM 0x40003
 #define ARCH_CPU_64BIT
 #define ARCH_RISCV
+#define ARCH_RISCV_FPU
+#define ARCH_RISCV_FPU_S
 #define ARCH_RISCV64
 
 /* RT-Thread Components */
diff --git a/bsp/k210/rtconfig.py b/bsp/k210/rtconfig.py
index b9258cd374..0f336d545e 100755
--- a/bsp/k210/rtconfig.py
+++ b/bsp/k210/rtconfig.py
@@ -38,7 +38,7 @@ if PLATFORM == 'gcc':
     OBJDUMP = PREFIX + 'objdump'
     OBJCPY  = PREFIX + 'objcopy'
 
-    DEVICE  = ' -mcmodel=medany -march=rv64imafdc -mabi=lp64d'
+    DEVICE  = ' -mcmodel=medany -march=rv64imafc -mabi=lp64f -fsingle-precision-constant'
     CFLAGS  = DEVICE + ' -fno-common -ffunction-sections -fdata-sections -fstrict-volatile-bitfields'
     AFLAGS  = ' -c' + DEVICE + ' -x assembler-with-cpp'
     LFLAGS  = DEVICE + ' -nostartfiles -Wl,--gc-sections,-Map=rtthread.map,-cref,-u,_start -T link.lds'
diff --git a/libcpu/Kconfig b/libcpu/Kconfig
index ae2767dec9..974c421138 100644
--- a/libcpu/Kconfig
+++ b/libcpu/Kconfig
@@ -106,6 +106,14 @@ config ARCH_RISCV
 config ARCH_RISCV_FPU
     bool
 
+config ARCH_RISCV_FPU_S
+    select ARCH_RISCV_FPU
+    bool
+
+config ARCH_RISCV_FPU_D
+    select ARCH_RISCV_FPU
+    bool
+
 config ARCH_RISCV32
     select ARCH_RISCV
     bool
diff --git a/libcpu/risc-v/common/context_gcc.S b/libcpu/risc-v/common/context_gcc.S
index 5c9f05c4e8..9f356f4191 100644
--- a/libcpu/risc-v/common/context_gcc.S
+++ b/libcpu/risc-v/common/context_gcc.S
@@ -7,6 +7,7 @@
  * Date           Author       Notes
  * 2018/10/28     Bernard      The unify RISC-V porting implementation
  * 2018/12/27     Jesven       Add SMP support
+ * 2020/11/20     BalanceTWK   Add FPU support
  */
 
 #include "cpuport.h"
@@ -72,6 +73,43 @@ rt_hw_context_switch:
      *     mstatus.mie -> sp(2)
      *     x(i)        -> sp(i-4)
      */
+#ifdef ARCH_RISCV_FPU
+    addi    sp, sp, -32 * FREGBYTES
+
+    FSTORE  f0, 0 * FREGBYTES(sp)
+    FSTORE  f1, 1 * FREGBYTES(sp)
+    FSTORE  f2, 2 * FREGBYTES(sp)
+    FSTORE  f3, 3 * FREGBYTES(sp)
+    FSTORE  f4, 4 * FREGBYTES(sp)
+    FSTORE  f5, 5 * FREGBYTES(sp)
+    FSTORE  f6, 6 * FREGBYTES(sp)
+    FSTORE  f7, 7 * FREGBYTES(sp)
+    FSTORE  f8, 8 * FREGBYTES(sp)
+    FSTORE  f9, 9 * FREGBYTES(sp)
+    FSTORE  f10, 10 * FREGBYTES(sp)
+    FSTORE  f11, 11 * FREGBYTES(sp)
+    FSTORE  f12, 12 * FREGBYTES(sp)
+    FSTORE  f13, 13 * FREGBYTES(sp)
+    FSTORE  f14, 14 * FREGBYTES(sp)
+    FSTORE  f15, 15 * FREGBYTES(sp)
+    FSTORE  f16, 16 * FREGBYTES(sp)
+    FSTORE  f17, 17 * FREGBYTES(sp)
+    FSTORE  f18, 18 * FREGBYTES(sp)
+    FSTORE  f19, 19 * FREGBYTES(sp)
+    FSTORE  f20, 20 * FREGBYTES(sp)
+    FSTORE  f21, 21 * FREGBYTES(sp)
+    FSTORE  f22, 22 * FREGBYTES(sp)
+    FSTORE  f23, 23 * FREGBYTES(sp)
+    FSTORE  f24, 24 * FREGBYTES(sp)
+    FSTORE  f25, 25 * FREGBYTES(sp)
+    FSTORE  f26, 26 * FREGBYTES(sp)
+    FSTORE  f27, 27 * FREGBYTES(sp)
+    FSTORE  f28, 28 * FREGBYTES(sp)
+    FSTORE  f29, 29 * FREGBYTES(sp)
+    FSTORE  f30, 30 * FREGBYTES(sp)
+    FSTORE  f31, 31 * FREGBYTES(sp)
+
+#endif
     addi  sp,  sp, -32 * REGBYTES
     STORE sp,  (a0)
 
@@ -174,7 +212,7 @@ rt_hw_context_switch_exit:
 
     LOAD x1,   1 * REGBYTES(sp)
 
-    li    t0, 0x00001800
+    li    t0, 0x00007800
     csrw  mstatus, t0
     LOAD a0,   2 * REGBYTES(sp)
     csrs mstatus, a0
@@ -209,4 +247,42 @@ rt_hw_context_switch_exit:
     LOAD x31, 31 * REGBYTES(sp)
 
     addi sp,  sp, 32 * REGBYTES
+
+#ifdef ARCH_RISCV_FPU
+    FLOAD   f0, 0 * FREGBYTES(sp)
+    FLOAD   f1, 1 * FREGBYTES(sp)
+    FLOAD   f2, 2 * FREGBYTES(sp)
+    FLOAD   f3, 3 * FREGBYTES(sp)
+    FLOAD   f4, 4 * FREGBYTES(sp)
+    FLOAD   f5, 5 * FREGBYTES(sp)
+    FLOAD   f6, 6 * FREGBYTES(sp)
+    FLOAD   f7, 7 * FREGBYTES(sp)
+    FLOAD   f8, 8 * FREGBYTES(sp)
+    FLOAD   f9, 9 * FREGBYTES(sp)
+    FLOAD   f10, 10 * FREGBYTES(sp)
+    FLOAD   f11, 11 * FREGBYTES(sp)
+    FLOAD   f12, 12 * FREGBYTES(sp)
+    FLOAD   f13, 13 * FREGBYTES(sp)
+    FLOAD   f14, 14 * FREGBYTES(sp)
+    FLOAD   f15, 15 * FREGBYTES(sp)
+    FLOAD   f16, 16 * FREGBYTES(sp)
+    FLOAD   f17, 17 * FREGBYTES(sp)
+    FLOAD   f18, 18 * FREGBYTES(sp)
+    FLOAD   f19, 19 * FREGBYTES(sp)
+    FLOAD   f20, 20 * FREGBYTES(sp)
+    FLOAD   f21, 21 * FREGBYTES(sp)
+    FLOAD   f22, 22 * FREGBYTES(sp)
+    FLOAD   f23, 23 * FREGBYTES(sp)
+    FLOAD   f24, 24 * FREGBYTES(sp)
+    FLOAD   f25, 25 * FREGBYTES(sp)
+    FLOAD   f26, 26 * FREGBYTES(sp)
+    FLOAD   f27, 27 * FREGBYTES(sp)
+    FLOAD   f28, 28 * FREGBYTES(sp)
+    FLOAD   f29, 29 * FREGBYTES(sp)
+    FLOAD   f30, 30 * FREGBYTES(sp)
+    FLOAD   f31, 31 * FREGBYTES(sp)
+
+    addi    sp, sp, 32 * FREGBYTES
+#endif
+
     mret
diff --git a/libcpu/risc-v/common/cpuport.c b/libcpu/risc-v/common/cpuport.c
index a44dc40f79..7542f65855 100644
--- a/libcpu/risc-v/common/cpuport.c
+++ b/libcpu/risc-v/common/cpuport.c
@@ -6,6 +6,7 @@
  * Change Logs:
  * Date           Author       Notes
  * 2018/10/28     Bernard      The unify RISC-V porting code.
+ * 2020/11/20     BalanceTWK   Add FPU support
  */
 
 #include <rthw.h>
@@ -53,6 +54,40 @@ struct rt_hw_stack_frame
     rt_ubase_t t4;         /* x29 - t4     - temporary register 4                */
     rt_ubase_t t5;         /* x30 - t5     - temporary register 5                */
     rt_ubase_t t6;         /* x31 - t6     - temporary register 6                */
+#ifdef ARCH_RISCV_FPU
+    rv_floatreg_t f0;      /* f0  */
+    rv_floatreg_t f1;      /* f1  */
+    rv_floatreg_t f2;      /* f2  */
+    rv_floatreg_t f3;      /* f3  */
+    rv_floatreg_t f4;      /* f4  */
+    rv_floatreg_t f5;      /* f5  */
+    rv_floatreg_t f6;      /* f6  */
+    rv_floatreg_t f7;      /* f7  */
+    rv_floatreg_t f8;      /* f8  */
+    rv_floatreg_t f9;      /* f9  */
+    rv_floatreg_t f10;     /* f10 */
+    rv_floatreg_t f11;     /* f11 */
+    rv_floatreg_t f12;     /* f12 */
+    rv_floatreg_t f13;     /* f13 */
+    rv_floatreg_t f14;     /* f14 */
+    rv_floatreg_t f15;     /* f15 */
+    rv_floatreg_t f16;     /* f16 */
+    rv_floatreg_t f17;     /* f17 */
+    rv_floatreg_t f18;     /* f18 */
+    rv_floatreg_t f19;     /* f19 */
+    rv_floatreg_t f20;     /* f20 */
+    rv_floatreg_t f21;     /* f21 */
+    rv_floatreg_t f22;     /* f22 */
+    rv_floatreg_t f23;     /* f23 */
+    rv_floatreg_t f24;     /* f24 */
+    rv_floatreg_t f25;     /* f25 */
+    rv_floatreg_t f26;     /* f26 */
+    rv_floatreg_t f27;     /* f27 */
+    rv_floatreg_t f28;     /* f28 */
+    rv_floatreg_t f29;     /* f29 */
+    rv_floatreg_t f30;     /* f30 */
+    rv_floatreg_t f31;     /* f31 */
+#endif
 };
 
 /**
diff --git a/libcpu/risc-v/common/cpuport.h b/libcpu/risc-v/common/cpuport.h
index 95268732cb..d6cec2f0cf 100644
--- a/libcpu/risc-v/common/cpuport.h
+++ b/libcpu/risc-v/common/cpuport.h
@@ -6,6 +6,7 @@
  * Change Logs:
  * Date           Author       Notes
  * 2018-10-03     Bernard      The first version
+ * 2020/11/20     BalanceTWK   Add FPU support
  */
 
 #ifndef CPUPORT_H__
@@ -24,4 +25,19 @@
 #define REGBYTES                4
 #endif
 
+#ifdef ARCH_RISCV_FPU
+#ifdef ARCH_RISCV_FPU_D
+#define FSTORE                  fsd
+#define FLOAD                   fld
+#define FREGBYTES               8
+#define rv_floatreg_t           rt_int64_t  	       
+#endif
+#ifdef ARCH_RISCV_FPU_S
+#define FSTORE                  fsw
+#define FLOAD                   flw
+#define FREGBYTES               4
+#define rv_floatreg_t           rt_int32_t  	       
+#endif
+#endif
+
 #endif
diff --git a/libcpu/risc-v/k210/interrupt_gcc.S b/libcpu/risc-v/k210/interrupt_gcc.S
index 0393ea51f8..dc4a720dea 100644
--- a/libcpu/risc-v/k210/interrupt_gcc.S
+++ b/libcpu/risc-v/k210/interrupt_gcc.S
@@ -15,6 +15,43 @@
   .align 2
   .global trap_entry
 trap_entry:
+#ifdef ARCH_RISCV_FPU
+    addi    sp, sp, -32 * FREGBYTES
+
+    FSTORE  f0, 0 * FREGBYTES(sp)
+    FSTORE  f1, 1 * FREGBYTES(sp)
+    FSTORE  f2, 2 * FREGBYTES(sp)
+    FSTORE  f3, 3 * FREGBYTES(sp)
+    FSTORE  f4, 4 * FREGBYTES(sp)
+    FSTORE  f5, 5 * FREGBYTES(sp)
+    FSTORE  f6, 6 * FREGBYTES(sp)
+    FSTORE  f7, 7 * FREGBYTES(sp)
+    FSTORE  f8, 8 * FREGBYTES(sp)
+    FSTORE  f9, 9 * FREGBYTES(sp)
+    FSTORE  f10, 10 * FREGBYTES(sp)
+    FSTORE  f11, 11 * FREGBYTES(sp)
+    FSTORE  f12, 12 * FREGBYTES(sp)
+    FSTORE  f13, 13 * FREGBYTES(sp)
+    FSTORE  f14, 14 * FREGBYTES(sp)
+    FSTORE  f15, 15 * FREGBYTES(sp)
+    FSTORE  f16, 16 * FREGBYTES(sp)
+    FSTORE  f17, 17 * FREGBYTES(sp)
+    FSTORE  f18, 18 * FREGBYTES(sp)
+    FSTORE  f19, 19 * FREGBYTES(sp)
+    FSTORE  f20, 20 * FREGBYTES(sp)
+    FSTORE  f21, 21 * FREGBYTES(sp)
+    FSTORE  f22, 22 * FREGBYTES(sp)
+    FSTORE  f23, 23 * FREGBYTES(sp)
+    FSTORE  f24, 24 * FREGBYTES(sp)
+    FSTORE  f25, 25 * FREGBYTES(sp)
+    FSTORE  f26, 26 * FREGBYTES(sp)
+    FSTORE  f27, 27 * FREGBYTES(sp)
+    FSTORE  f28, 28 * FREGBYTES(sp)
+    FSTORE  f29, 29 * FREGBYTES(sp)
+    FSTORE  f30, 30 * FREGBYTES(sp)
+    FSTORE  f31, 31 * FREGBYTES(sp)
+
+#endif
 
     /* save thread context to thread stack */
     addi sp, sp, -32 * REGBYTES
diff --git a/libcpu/risc-v/k210/startup_gcc.S b/libcpu/risc-v/k210/startup_gcc.S
index f5c0d8fa94..cc7126e8ab 100644
--- a/libcpu/risc-v/k210/startup_gcc.S
+++ b/libcpu/risc-v/k210/startup_gcc.S
@@ -67,38 +67,38 @@ _start:
   csrs mstatus, t0
 
   fssr    x0
-  fmv.d.x f0, x0
-  fmv.d.x f1, x0
-  fmv.d.x f2, x0
-  fmv.d.x f3, x0
-  fmv.d.x f4, x0
-  fmv.d.x f5, x0
-  fmv.d.x f6, x0
-  fmv.d.x f7, x0
-  fmv.d.x f8, x0
-  fmv.d.x f9, x0
-  fmv.d.x f10,x0
-  fmv.d.x f11,x0
-  fmv.d.x f12,x0
-  fmv.d.x f13,x0
-  fmv.d.x f14,x0
-  fmv.d.x f15,x0
-  fmv.d.x f16,x0
-  fmv.d.x f17,x0
-  fmv.d.x f18,x0
-  fmv.d.x f19,x0
-  fmv.d.x f20,x0
-  fmv.d.x f21,x0
-  fmv.d.x f22,x0
-  fmv.d.x f23,x0
-  fmv.d.x f24,x0
-  fmv.d.x f25,x0
-  fmv.d.x f26,x0
-  fmv.d.x f27,x0
-  fmv.d.x f28,x0
-  fmv.d.x f29,x0
-  fmv.d.x f30,x0
-  fmv.d.x f31,x0
+  fmv.w.x f0, x0
+  fmv.w.x f1, x0
+  fmv.w.x f2, x0
+  fmv.w.x f3, x0
+  fmv.w.x f4, x0
+  fmv.w.x f5, x0
+  fmv.w.x f6, x0
+  fmv.w.x f7, x0
+  fmv.w.x f8, x0
+  fmv.w.x f9, x0
+  fmv.w.x f10,x0
+  fmv.w.x f11,x0
+  fmv.w.x f12,x0
+  fmv.w.x f13,x0
+  fmv.w.x f14,x0
+  fmv.w.x f15,x0
+  fmv.w.x f16,x0
+  fmv.w.x f17,x0
+  fmv.w.x f18,x0
+  fmv.w.x f19,x0
+  fmv.w.x f20,x0
+  fmv.w.x f21,x0
+  fmv.w.x f22,x0
+  fmv.w.x f23,x0
+  fmv.w.x f24,x0
+  fmv.w.x f25,x0
+  fmv.w.x f26,x0
+  fmv.w.x f27,x0
+  fmv.w.x f28,x0
+  fmv.w.x f29,x0
+  fmv.w.x f30,x0
+  fmv.w.x f31,x0
 
 .option push
 .option norelax