PUSHA/PUSHAD -- Push all General Registers

PUSHA/PUSHAD -- Push all General Registers Opcode Instruction Clocks Description 60 PUSHA 18 Push AX, CX, DX, BX, original SP, BP, SI, and DI 60 PUSHAD 18 Push EAX, ECX, EDX, EBX, original ESP, EBP, ESI, and EDI Operation IF OperandSize = 16 (* PUSHA instruction *) THEN Temp = (SP); Push(AX); Push(CX); Push(DX); Push(BX); Push(Temp); Push(BP); Push(SI); Push(DI); ELSE (* OperandSize = 32, PUSHAD instruction *) Temp = (ESP); Push(EAX); Push(ECX); Push(EDX); Push(EBX); Push(Temp); Push(EBP); Push(ESI); Push(EDI); FI; Description PUSHA and PUSHAD save the 16-bit or 32-bit general registers, respectively, on the 80386 stack. PUSHA decrements the stack pointer (SP) by 16 to hold the eight word values. PUSHAD decrements the stack pointer (ESP) by 32 to hold the eight doubleword values. Because the registers are pushed onto the stack in the order in which they were given, they appear in the 16 or 32 new stack bytes in reverse order. The last register pushed is DI or EDI. Flags Affected None Protected Mode Exceptions #SS(0) if the starting or ending stack address is outside the stack segment limit; #PF(fault-code) for a page fault Real Address Mode Exceptions Before executing PUSHA or PUSHAD, the 80386 shuts down if SP or ESP equals 1, 3, or 5; if SP or ESP equals 7, 9, 11, 13, or 15, exception 13 occurs Virtual 8086 Mode Exceptions Same exceptions as in real-address mode; #PF(fault-code) for a page fault