h8s-2169 Renesas Electronics Corporation., h8s-2169 Datasheet - Page 128

• Manufacturer Part Number: h8s-2169
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 4 Exception Handling
4.6
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:
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 Rn (or MOV.W @SP+, Rn)
POP.L ERn (or MOV.L @SP+, ERn)
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.
Rev. 3.00 Jan 18, 2006 page 100 of 1044
REJ09B0280-0300
Legend:
CCR: Condition-code register
PC:
R1L: General register R1L
SP:
Note: This diagram illustrates an example in which the interrupt control mode is 0, in advanced
SP
Stack pointer
Program counter
mode.
Notes on Use of the Stack
SP set to H'FFFEFF
TRAP instruction executed
Figure 4.6 Operation when SP Value is Odd
SP
Data saved above SP
CCR
PC
MOV.B R1L, @–ER7
SP
Contents of CCR lost
R1L
PC
H'FFFEFA
H'FFFEFB
H'FFFEFC
H'FFFEFD
H'FFFEFF