package regnum

import (
	"fmt"
	"strings"
)

// The mapping between hardware registers and DWARF registers is specified
// in the System V ABI AMD64 Architecture Processor Supplement page 57,
// figure 3.36
// https://www.uclibc.org/docs/psABI-x86_64.pdf

const (
	AMD64_Rax     = 0
	AMD64_Rdx     = 1
	AMD64_Rcx     = 2
	AMD64_Rbx     = 3
	AMD64_Rsi     = 4
	AMD64_Rdi     = 5
	AMD64_Rbp     = 6
	AMD64_Rsp     = 7
	AMD64_R8      = 8
	AMD64_R9      = 9
	AMD64_R10     = 10
	AMD64_R11     = 11
	AMD64_R12     = 12
	AMD64_R13     = 13
	AMD64_R14     = 14
	AMD64_R15     = 15
	AMD64_Rip     = 16
	AMD64_XMM0    = 17 // XMM1 through XMM15 follow
	AMD64_ST0     = 33 // ST(1) through ST(7) follow
	AMD64_Rflags  = 49
	AMD64_Es      = 50
	AMD64_Cs      = 51
	AMD64_Ss      = 52
	AMD64_Ds      = 53
	AMD64_Fs      = 54
	AMD64_Gs      = 55
	AMD64_Fs_base = 58
	AMD64_Gs_base = 59
	AMD64_MXCSR   = 64
	AMD64_CW      = 65
	AMD64_SW      = 66
)

var amd64DwarfToName = map[uint64]string{
	AMD64_Rax:       "Rax",
	AMD64_Rdx:       "Rdx",
	AMD64_Rcx:       "Rcx",
	AMD64_Rbx:       "Rbx",
	AMD64_Rsi:       "Rsi",
	AMD64_Rdi:       "Rdi",
	AMD64_Rbp:       "Rbp",
	AMD64_Rsp:       "Rsp",
	AMD64_R8:        "R8",
	AMD64_R9:        "R9",
	AMD64_R10:       "R10",
	AMD64_R11:       "R11",
	AMD64_R12:       "R12",
	AMD64_R13:       "R13",
	AMD64_R14:       "R14",
	AMD64_R15:       "R15",
	AMD64_Rip:       "Rip",
	AMD64_XMM0:      "XMM0",
	AMD64_XMM0 + 1:  "XMM1",
	AMD64_XMM0 + 2:  "XMM2",
	AMD64_XMM0 + 3:  "XMM3",
	AMD64_XMM0 + 4:  "XMM4",
	AMD64_XMM0 + 5:  "XMM5",
	AMD64_XMM0 + 6:  "XMM6",
	AMD64_XMM0 + 7:  "XMM7",
	AMD64_XMM0 + 8:  "XMM8",
	AMD64_XMM0 + 9:  "XMM9",
	AMD64_XMM0 + 10: "XMM10",
	AMD64_XMM0 + 11: "XMM11",
	AMD64_XMM0 + 12: "XMM12",
	AMD64_XMM0 + 13: "XMM13",
	AMD64_XMM0 + 14: "XMM14",
	AMD64_XMM0 + 15: "XMM15",
	AMD64_ST0:       "ST(0)",
	AMD64_ST0 + 1:   "ST(1)",
	AMD64_ST0 + 2:   "ST(2)",
	AMD64_ST0 + 3:   "ST(3)",
	AMD64_ST0 + 4:   "ST(4)",
	AMD64_ST0 + 5:   "ST(5)",
	AMD64_ST0 + 6:   "ST(6)",
	AMD64_ST0 + 7:   "ST(7)",
	AMD64_Rflags:    "Rflags",
	AMD64_Es:        "Es",
	AMD64_Cs:        "Cs",
	AMD64_Ss:        "Ss",
	AMD64_Ds:        "Ds",
	AMD64_Fs:        "Fs",
	AMD64_Gs:        "Gs",
	AMD64_Fs_base:   "Fs_base",
	AMD64_Gs_base:   "Gs_base",
	AMD64_MXCSR:     "MXCSR",
	AMD64_CW:        "CW",
	AMD64_SW:        "SW",
}

var AMD64NameToDwarf = func() map[string]int {
	r := make(map[string]int)
	for regNum, regName := range amd64DwarfToName {
		r[strings.ToLower(regName)] = int(regNum)
	}
	r["eflags"] = 49
	r["st0"] = 33
	r["st1"] = 34
	r["st2"] = 35
	r["st3"] = 36
	r["st4"] = 37
	r["st5"] = 38
	r["st6"] = 39
	r["st7"] = 40
	return r
}()

func AMD64MaxRegNum() uint64 {
	max := uint64(AMD64_Rip)
	for i := range amd64DwarfToName {
		if i > max {
			max = i
		}
	}
	return max
}

func AMD64ToName(num uint64) string {
	name, ok := amd64DwarfToName[num]
	if ok {
		return name
	}
	return fmt.Sprintf("unknown%d", num)
}