25--31Undefined
}
(2)扩展指令
1.第 80000000 号功能(EAX=80000000h)
调用寄存器:
EAX=80000000h
返回寄存器:
EBX,ECX,EDX=保留
EAX=最大功能号
2.第 80000001 号功能
调用寄存器:
EAX=80000001h
返回寄存器:
EAX=CPU 说明(见第 1 号功能)
EDX=扩展特征标志字
{
EDX[0]<- FPU: FPU on Chip
EDX[1] <- VME: Virtual Mode Extention present
EDX[2] <- DE: Debbuging Extentions
EDX[3] <- PSE: CPU support 4MB size pages
EDX[4] <- TSC: TSC present (See RDTSC command)
EDX[5] <- MSR: CPU have K5 Compatible MSRs
EDX[6] <- 0 (Reserved)
EDX[7] <- MCE: Machine Check exception
EDX[8] <- CX8: Support CMPXCHG8B instruction
EDX[9] <- Reserved
EDX[10]<- Support SYSCALL and SYSRET instruction (!!!)
EDX[11,12]<- reserved
EDX[13]<- PGE: Page Global Feature support
EDX[14]<- reserved
EDX[15]<- CMOV: CPU support CMOV instruction
EDX[16]<- FCMOV: CPU support FP. FCMOV (!!!)
EDX[22..16] <- Reserved
EDX[23] <- MMX: CPU support IA MMX
EDX[24] <- (Cyrix) Cyrix Extended MMX
EDX[30..24] <- Reserved
EDX[31] <- AMD 3DNow!
}
(附录 1)各类 CPU 参数
1. Cyrix
厂商识别串: "CyrixInstead"
CPU 名称 家族 型号