h8s-2635 Renesas Electronics Corporation., h8s-2635 Datasheet - Page 163

• Manufacturer Part Number: h8s-2635
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

4.7
When accessing word data or longword data, the chip 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:
Use the following instructions to restore registers:
Setting SP to an odd value may lead to a malfunction. Figure 4-6 shows an example of what
happens when the SP value is odd.
PUSH.W
PUSH.L
POP.W
POP.L
SP
Notes on Use of the Stack
Note: This diagram illustrates an example in which the interrupt control mode
Legend:
SP set to H'FFFEFF
Rn
ERn
Rn
ERn
is 0, in advanced mode.
TRAP instruction executed
CCR: Condition code register
PC:
R1L: General register R1L
SP:
(or MOV.W Rn, @-SP)
(or MOV.L ERn, @-SP)
(or MOV.W @SP+, Rn)
(or MOV.L @SP+, ERn)
Figure 4-6 Operation when SP Value Is Odd
Stack pointer
Program counter
SP
Data saved above SP
CCR
PC
MOV.B R1L, @−ER7
Rev. 6.00 Feb 22, 2005 page 103 of 1484
SP
Contents of CCR lost
Section 4 Exception Handling
R1L
PC
REJ09B0103-0600
H'FFFEFA
H'FFFEFB
H'FFFEFC
H'FFFEFD
H'FFFEFF