- | The push, pushm, pop, and popm instructions are directives that are not available in the device. |
They push the values of specified registers to the stack area or pop the values of specified registers from the stack area.
- | In asrh, these instructions should be specified in the following formats. |
- | pushm reg1, reg2, ..., regN |
- | popm reg1, reg2, ..., regN |
- | The instructions are expanded as shown below and multiple machine-language instructions are generated. |
|
|
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push reg1
|
add -4, sp
st.w reg1, 0[sp]
|
pushm reg1, reg2, …, regN
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addi -4 * N, sp, sp
st.w regN, 4 * (N - 1)[sp]
:
st.w reg2, 4 * 1[sp]
st.w reg1, 4 * 0[sp]
|
pop reg1
|
ld.w 0[sp], reg1
add 4, sp
|
popm reg1, reg2, …, regN
|
ld.w 4 * 0[sp], reg1
ld.w 4 * 1[sp], reg2
:
ld.w 4 * (N - 1)[sp], regN
addi 4 * N, sp, sp
|
Note | The values of PSW are undefined because the add or addi instruction is used.
We recommend the use of the pushsp or popsp instruction provided by the device. |