Hitachi H8/500 Series Hardware Manual page 79

Specifically, the LDC.B and STC.B instructions are executed as follows.
The following applies only to the stack-pointer addressing modes. In addressing modes that do not
use the stack pointer, byte data access is performed as specified by the assembler mnemonic.
(1)
STC.B EP, @–SP
When word data access is applied to EP, both EP and DP are accessed. This instruction
stores EP at address SP (old) –2, and DP at address SP (old) –1.
Old SP – 2
Old SP – 1
Old SP
(2)
LDC.B @SP+, EP
When word data access is applied to EP, both EP and DP are accessed. This instruction
loads EP from address SP (old), and DP from address SP (old) +1, updating the DP value as
well as the EP value.
Old SP
Old SP + 1
Old SP + 2
(3)
STC.B CCR, @–SP
When word data access is applied to CCR, only CCR is accessed. This instruction stores
identical CCR contents at both address SP (old) –2 and address SP (old) –1.
Old SP – 2
Old SP – 1
Old SP
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Before execution
EP
a
a
b
DP
b
Before execution
Before execution
EP
a
New SP
New SP + 1
DP
b
New SP + 2
New SP – 2
New SP – 1
New SP
CCR
a
New SP
New SP + 1
New SP + 2
60
a
b
After execution
EP
a
DP
b
After execution
a
b
After execution