{name: "FSUBS", argLength: 2, reg: fp21clobber, typ: "(Float32,Flags)", asm: "FSUBS", resultInArg0: true},                    // fp32 arg0 - arg1
		{name: "FSUB", argLength: 2, reg: fp21clobber, typ: "(Float64,Flags)", asm: "FSUB", resultInArg0: true},                      // fp64 arg0 - arg1

	FNMADDCC:       "fnmadd.",
	FNMSUB:         "fnmsub",
	FNMSUBCC:       "fnmsub.",
	FRSP:           "frsp",
	FRSPCC:         "frsp.",
	FSUB:           "fsub",
	FSUBCC:         "fsub.",
	ISYNC:          "isync",
	LBZ:            "lbz",
	LBZU:           "lbzu",
	LBZUX:          "lbzux",
	LBZX:           "lbzx",
	LFD:            "lfd",
	LFDU:           "lfdu",
	LFDUX:          "lfdux",

(Add(64|Ptr) ...) => (ADD ...)
(Add(32|16|8) ...) => (ADDW ...)
(Add32F x y) => (Select0 (FADDS x y))
(Add64F x y) => (Select0 (FADD x y))

(Sub(64|Ptr) ...) => (SUB ...)
(Sub(32|16|8) ...) => (SUBW ...)
(Sub32F x y) => (Select0 (FSUBS x y))
(Sub64F x y) => (Select0 (FSUB x y))

(Mul64 ...) => (MULLD ...)
(Mul(32|16|8) ...) => (MULLW ...)
(Mul32F ...) => (FMULS ...)
(Mul64F ...) => (FMUL ...)
(Mul64uhilo ...) => (MLGR ...)

	"RDTIME",
	"RDTIMEH",
	"RDINSTRET",
	"RDINSTRETH",
	"FRCSR",
	"FSCSR",
	"FRRM",
	"FSRM",
	"FRFLAGS",
	"FSFLAGS",
	"FSRMI",
	"FSFLAGSI",
	"FLW",
	"FSW",
	"FADDS",
	"FSUBS",
	"FMULS",
	"FDIVS",
	"FMINS",
	"FMAXS",
	"FSQRTS",
	"FMADDS",
	"FMSUBS",
	"FNMADDS",
	"FNMSUBS",
	"FCVTWS",
	"FCVTLS",
	"FCVTSW",
	"FCVTSL",
	"FCVTWUS",
	"FCVTLUS",

(MSUB a (MOVDconst [-1]) x) => (ADD a x)
(MSUB a (MOVDconst [0]) _) => a
(MSUB a (MOVDconst [1]) x) => (SUB a x)
(MSUB a (MOVDconst [c]) x) && isPowerOfTwo64(c) => (SUBshiftLL a x [log64(c)])
(MSUB a (MOVDconst [c]) x) && isPowerOfTwo64(c-1) && c>=3 => (SUB a (ADDshiftLL <x.Type> x x [log64(c-1)]))
(MSUB a (MOVDconst [c]) x) && isPowerOfTwo64(c+1) && c>=7 => (ADD a (SUBshiftLL <x.Type> x x [log64(c+1)]))

	"FRINTMS",
	"FRINTND",
	"FRINTNS",
	"FRINTPD",
	"FRINTPS",
	"FRINTXD",
	"FRINTXS",
	"FRINTZD",
	"FRINTZS",
	"FSQRTD",
	"FSQRTS",
	"FSTPD",
	"FSTPQ",
	"FSTPS",
	"FSUBD",
	"FSUBS",
	"HINT",
	"HLT",
	"HVC",
	"IC",
	"ISB",
	"LDADDAB",
	"LDADDAD",
	"LDADDAH",
	"LDADDALB",
	"LDADDALD",
	"LDADDALH",
	"LDADDALW",
	"LDADDAW",
	"LDADDB",
	"LDADDD",

// and will not run on earlier targets.
//
(Add(Ptr|64|32|16|8) ...) => (ADD ...)
(Add64F ...) => (FADD ...)
(Add32F ...) => (FADDS ...)

(Sub(Ptr|64|32|16|8) ...) => (SUB ...)
(Sub32F ...) => (FSUBS ...)
(Sub64F ...) => (FSUB ...)

(Min(32|64)F x y) && buildcfg.GOPPC64 >= 9 => (XSMINJDP x y)
(Max(32|64)F x y) && buildcfg.GOPPC64 >= 9 => (XSMAXJDP x y)

// Combine 64 bit integer multiply and adds

)

// A SubFS is a file system with a Sub method.
type SubFS interface {
	FS

	// Sub returns an FS corresponding to the subtree rooted at dir.
	Sub(dir string) (FS, error)
}

// Sub returns an [FS] corresponding to the subtree rooted at fsys's dir.
//
// If dir is ".", Sub returns fsys unchanged.
// Otherwise, if fs implements [SubFS], Sub returns fsys.Sub(dir).
// Otherwise, Sub returns a new [FS] implementation sub that,

# Sub-dependencies

You can create dependencies that have **sub-dependencies**.

They can be as **deep** as you need them to be.

**FastAPI** will take care of solving them.

## First dependency "dependable"

You could create a first dependency ("dependable") like:

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial005_an_py310.py!}
    ```

=== "Python 3.9+"

下图显示的是主应用 API 文档，只包括其自有的*路径操作*。

<img src="/img/tutorial/sub-applications/image01.png">

然后查看子应用文档 <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs。</a>

下图显示的是子应用的 API 文档，也是只包括其自有的*路径操作*，所有这些路径操作都在 `/subapi` 子路径前缀下。

<img src="/img/tutorial/sub-applications/image02.png">

两个用户界面都可以正常运行，因为浏览器能够与每个指定的应用或子应用会话。

### 技术细节：`root_path`