HD64F2357VF13 Datasheet, PDF (109/1049 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

4.7 Notes on Use of the Stack
When accessing word data or longword data, the H8S/2357 Group assumes that the lowest address bit is 0. The stack
should always be accessed by word transfer instruction or longword transfer instruction, and the value of the stack pointer
(SP, ER7) should always be kept even. Use the following instructions to save registers:
PUSH.W Rn (or MOV.W Rn, @-SP)
PUSH.L ERn (or MOV.L ERn, @-SP)
Use the following instructions to restore registers:
POP.W
POP.L
Rn (or MOV.W @SP+, Rn)
ERn (or MOV.L @SP+, ERn)
Setting SP to an odd value may lead to a malfunction. Figure 4-5 shows an example of what happens when the SP value is
odd.
CCR
SP
SP
PC
R1L
H'FFFEFA
H'FFFEFB
PC
H'FFFEFC
H'FFFEFD
SP
H'FFFEFF
TRAPA instruction executed MOV.B R1L, @–ER7
SP set to H'FFFEFF Data saved above SP Contents of CCR lost
Legend:
CCR: Condition code register
PC: Program counter
R1L: General register R1L
SP: Stack pointer
Note: This diagram illustrates an example in which the interrupt control mode
is 0, in advanced mode.
Figure 4-5 Operation when SP Value is Odd
Rev.6.00 Oct.28.2004 page 79 of 1016
REJ09B0138-0600H