Transfer control to the return address located on the stack. Returns to a lesser privilege level cause the stack to be reloaded from the value saved beyond the parameter block.
#Cpusim bit problems code
The AR byte of the descriptor must indicate a code segment of equal or lesser privilege (or greater or equal numeric value) than the current privilege level.
In Protected mode, an intersegment return causes the processor to check the descriptor addressed by the return selector. In Real Mode, CS and IP are loaded directly. The offset is popped first, followed by the selector. Typically, these bytes or words are used as input parameters to the called procedure.įor an intersegment (far) return, the address on the stack is a long pointer. The optional numeric (16- or 32-bit) parameter to lret specifies the number of stack bytes or words to be released after the return address is popped from the stack. Issue the lret instruction within the called procedure to resume execution flow at the instruction following the call. This address is usually placed on the stack by an lcall instruction. The lret instruction transfers control to a return address located on the stack. Typically, these bytes or words are used as input parameters to the called procedure.įor an intersegment (near) return, the address on the stack is a segment offset that is popped onto the instruction pointer. The optional numeric (16- or 32-bit) parameter to ret specifies the number of stack bytes or words to be released after the return address is popped from the stack.
Issue the ret instruction within the called procedure to resume execution flow at the instruction following the call. This address is usually placed on the stack by a call instruction. The ret instruction transfers control to the return address located on the stack.
call *4(%edi) Return from Procedure (ret) ret 0x11111111Īdd a signed offset value to the address of the next instruction. After the procedure completes, the offset is popped by a near ret instruction within the procedure.īoth forms of the call instruction have no affect on the CS register. The offset of the instruction following the call instruction is pushed onto the stack. Procedure Call and Return Instructions Far Call - Procedure Call (lcall) lcall immptrįar call ptr16: specifies a register or memory location from which the absolute segment offset is fetched.
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