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jsr_w † c9 1100 1001 4: branchbyte1, branchbyte2, branchbyte3, branchbyte4 → address jump to subroutine at branchoffset (signed int constructed from unsigned bytes branchbyte1 << 24 | branchbyte2 << 16 | branchbyte3 << 8 | branchbyte4) and place the return address on the stack l2d 8a 1000 1010 value → result convert a long to a double l2f 89
For example, to move the cursor to (10, 15), needed, in 6502 assembler: LDA #31: JSR OSWRCH \ move text cursor LDA #10: JSR OSWRCH \ x-coordinate LDA #15: JSR OSWRCH \ y-coordinate (LDA loads a value into the accumulator; JSR is "jump to subroutine".) On the third OS call, the cursor will move.
Next, up to 63 word arguments may be placed on the stack. The caller then adds the number of arguments to the MARK opcode and pushes that result on the stack. The value of SP is copied to R5. Finally, a JSR PC,address is executed to call the subroutine. After executing its code, the subroutine terminates with an RTS R5. This loads the value in ...
When executing JSR (jump to subroutine) and RTS (return from subroutine) instructions, the return address pushed to the stack by JSR is that of the last byte of the JSR operand (that is, the most significant byte of the subroutine address), rather than the address of the following instruction.
They also added the BSR instruction, Branch to SubRoutine, which uses the same relative addressing mode with the JSR, Jump to SubRoutine. [ 1 ] In addition, the CE added 16-bit addressing, or "word relative", to all of the existing branch instructions.
Flow of control: JMP (jump), JSR (jump to subroutine), BSR (relative address jump to subroutine), RTS (return from subroutine), RTE (return from exception, i.e. an interrupt), TRAP (trigger a software exception similar to software interrupt), CHK (a conditional software exception)
Another advance was the jump to subroutine instruction, which combined the saving of the return address with the calling jump, thereby minimizing overhead significantly. In the IBM System/360 , for example, the branch instructions BAL or BALR, designed for procedure calling, would save the return address in a processor register specified in the ...
An indirect branch (also known as a computed jump, indirect jump and register-indirect jump) is a type of program control instruction present in some machine language instruction sets. Rather than specifying the address of the next instruction to execute , as in a direct branch , the argument specifies where the address is located.