[gcc r13-7232] LoongArch: Add built-in functions description of LoongArch Base instruction set instructions.

[gcc r13-7232] LoongArch: Add built-in functions description of LoongArch Base instruction set instructions.

[LuluCheng]

https://gcc.gnu.org/g:c5bfb2e08bd551539a2a6c686cf3020b1e8f6ad5

commit r13-7232-gc5bfb2e08bd551539a2a6c686cf3020b1e8f6ad5
Author: Lulu Cheng <chenglulu@loongson.cn>
Date:   Thu Apr 6 16:02:07 2023 +0800

    LoongArch: Add built-in functions description of LoongArch Base instruction set instructions.
    
    gcc/ChangeLog:
    
            * doc/extend.texi: Add section for LoongArch Base Built-in functions.
    
    (cherry picked from commit 5015cdf3155c80e5fd61f7b6ab8082ee849e3e90)

Diff:
---
 gcc/doc/extend.texi | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 0be838489e3..ac476801ed8 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -14674,6 +14674,7 @@ instructions, but allow the compiler to schedule those calls.
 * Blackfin Built-in Functions::
 * BPF Built-in Functions::
 * FR-V Built-in Functions::
+* LoongArch Base Built-in Functions::
 * MIPS DSP Built-in Functions::
 * MIPS Paired-Single Support::
 * MIPS Loongson Built-in Functions::
@@ -16203,6 +16204,134 @@ Use the @code{nldub} instruction to load the contents of address @var{x}
 into the data cache.  The instruction is issued in slot I1@.
 @end table
 
+@node LoongArch Base Built-in Functions
+@subsection LoongArch Base Built-in Functions
+
+These built-in functions are available for LoongArch.
+
+Data Type Description:
+@itemize
+@item @code{imm0_31}, a compile-time constant in range 0 to 31;
+@item @code{imm0_16383}, a compile-time constant in range 0 to 16383;
+@item @code{imm0_32767}, a compile-time constant in range 0 to 32767;
+@item @code{imm_n2048_2047}, a compile-time constant in range -2048 to 2047;
+@end itemize
+
+The intrinsics provided are listed below:
+@smallexample
+    unsigned int __builtin_loongarch_movfcsr2gr (imm0_31)
+    void __builtin_loongarch_movgr2fcsr (imm0_31, unsigned int)
+    void __builtin_loongarch_cacop_d (imm0_31, unsigned long int, imm_n2048_2047)
+    unsigned int __builtin_loongarch_cpucfg (unsigned int)
+    void __builtin_loongarch_asrtle_d (long int, long int)
+    void __builtin_loongarch_asrtgt_d (long int, long int)
+    long int __builtin_loongarch_lddir_d (long int, imm0_31)
+    void __builtin_loongarch_ldpte_d (long int, imm0_31)
+
+    int __builtin_loongarch_crc_w_b_w (char, int)
+    int __builtin_loongarch_crc_w_h_w (short, int)
+    int __builtin_loongarch_crc_w_w_w (int, int)
+    int __builtin_loongarch_crc_w_d_w (long int, int)
+    int __builtin_loongarch_crcc_w_b_w (char, int)
+    int __builtin_loongarch_crcc_w_h_w (short, int)
+    int __builtin_loongarch_crcc_w_w_w (int, int)
+    int __builtin_loongarch_crcc_w_d_w (long int, int)
+
+    unsigned int __builtin_loongarch_csrrd_w (imm0_16383)
+    unsigned int __builtin_loongarch_csrwr_w (unsigned int, imm0_16383)
+    unsigned int __builtin_loongarch_csrxchg_w (unsigned int, unsigned int, imm0_16383)
+    unsigned long int __builtin_loongarch_csrrd_d (imm0_16383)
+    unsigned long int __builtin_loongarch_csrwr_d (unsigned long int, imm0_16383)
+    unsigned long int __builtin_loongarch_csrxchg_d (unsigned long int, unsigned long int, imm0_16383)
+
+    unsigned char __builtin_loongarch_iocsrrd_b (unsigned int)
+    unsigned short __builtin_loongarch_iocsrrd_h (unsigned int)
+    unsigned int __builtin_loongarch_iocsrrd_w (unsigned int)
+    unsigned long int __builtin_loongarch_iocsrrd_d (unsigned int)
+    void __builtin_loongarch_iocsrwr_b (unsigned char, unsigned int)
+    void __builtin_loongarch_iocsrwr_h (unsigned short, unsigned int)
+    void __builtin_loongarch_iocsrwr_w (unsigned int, unsigned int)
+    void __builtin_loongarch_iocsrwr_d (unsigned long int, unsigned int)
+
+    void __builtin_loongarch_dbar (imm0_32767)
+    void __builtin_loongarch_ibar (imm0_32767)
+
+    void __builtin_loongarch_syscall (imm0_32767)
+    void __builtin_loongarch_break (imm0_32767)
+@end smallexample
+
+@emph{Note:}Since the control register is divided into 32-bit and 64-bit,
+but the access instruction is not distinguished. So GCC renames the control
+instructions when implementing intrinsics.
+
+Take the csrrd instruction as an example, built-in functions are implemented as follows:
+@smallexample
+  __builtin_loongarch_csrrd_w  // When reading the 32-bit control register use.
+  __builtin_loongarch_csrrd_d  // When reading the 64-bit control register use.
+@end smallexample
+
+For the convenience of use, the built-in functions are encapsulated,
+the encapsulated functions and @code{__drdtime_t, __rdtime_t} are
+defined in the @code{larchintrin.h}. So if you call the following
+function you need to include @code{larchintrin.h}.
+
+@smallexample
+     typedef struct drdtime@{
+            unsigned long dvalue;
+            unsigned long dtimeid;
+     @} __drdtime_t;
+
+     typedef struct rdtime@{
+            unsigned int value;
+            unsigned int timeid;
+     @} __rdtime_t;
+@end smallexample
+
+@smallexample
+    __drdtime_t __rdtime_d (void)
+    __rdtime_t  __rdtimel_w (void)
+    __rdtime_t  __rdtimeh_w (void)
+    unsigned int  __movfcsr2gr (imm0_31)
+    void __movgr2fcsr (imm0_31, unsigned int)
+    void __cacop_d (imm0_31, unsigned long, imm_n2048_2047)
+    unsigned int  __cpucfg (unsigned int)
+    void __asrtle_d (long int, long int)
+    void __asrtgt_d (long int, long int)
+    long int  __lddir_d (long int, imm0_31)
+    void __ldpte_d (long int, imm0_31)
+
+    int  __crc_w_b_w (char, int)
+    int  __crc_w_h_w (short, int)
+    int  __crc_w_w_w (int, int)
+    int  __crc_w_d_w (long int, int)
+    int  __crcc_w_b_w (char, int)
+    int  __crcc_w_h_w (short, int)
+    int  __crcc_w_w_w (int, int)
+    int  __crcc_w_d_w (long int, int)
+
+    unsigned int  __csrrd_w (imm0_16383)
+    unsigned int  __csrwr_w (unsigned int, imm0_16383)
+    unsigned int  __csrxchg_w (unsigned int, unsigned int, imm0_16383)
+    unsigned long  __csrrd_d (imm0_16383)
+    unsigned long  __csrwr_d (unsigned long, imm0_16383)
+    unsigned long  __csrxchg_d (unsigned long, unsigned long, imm0_16383)
+
+    unsigned char   __iocsrrd_b (unsigned int)
+    unsigned short  __iocsrrd_h (unsigned int)
+    unsigned int  __iocsrrd_w (unsigned int)
+    unsigned long  __iocsrrd_d (unsigned int)
+    void __iocsrwr_b (unsigned char, unsigned int)
+    void __iocsrwr_h (unsigned short, unsigned int)
+    void __iocsrwr_w (unsigned int, unsigned int)
+    void __iocsrwr_d (unsigned long, unsigned int)
+
+    void __dbar (imm0_32767)
+    void __ibar (imm0_32767)
+
+    void __syscall (imm0_32767)
+    void __break (imm0_32767)
+@end smallexample
+
 @node MIPS DSP Built-in Functions
 @subsection MIPS DSP Built-in Functions