Epson S5U1C62000A Manuel D’Utilisation
S5U1C62000A MANUAL
EPSON
79
(S1C60/62 FAMILY ASSEMBLER PACKAGE)
CHAPTER 5: ASSEMBLER
5.7.9 Area Securing Pseudo-Instructions (.comm, .lcomm)
Instruction format
.comm
<Symbol>[,] <Size>
.lcomm
<Symbol>[,] <Size>
<Symbol>:
Symbols for data memory access (address reference)
• The 1st character is limited to a–z, A–Z, ? and _.
• The 2nd and the subsequent character can use a–z, A–Z, 0–9, ? and _.
• Uppercase and lowercase are discriminated.
• One or more spaces or tabs are necessary between instruction and symbol.
• The 1st character is limited to a–z, A–Z, ? and _.
• The 2nd and the subsequent character can use a–z, A–Z, 0–9, ? and _.
• Uppercase and lowercase are discriminated.
• One or more spaces or tabs are necessary between instruction and symbol.
<Size>:
Number of words of the area to be secured (4 bits/word)
• Only decimal, binary and hexadecimal numbers can be described.
• The size that can grammatically be specified is from 0 to 8,192.
• One or more spaces, tabs or a comma (,) are necessary between symbol and size.
• Only decimal, binary and hexadecimal numbers can be described.
• The size that can grammatically be specified is from 0 to 8,192.
• One or more spaces, tabs or a comma (,) are necessary between symbol and size.
Sample description:
.comm
RAM0 4
.lcomm
BUF,1
Function
Sets an area of the specified size in the BSS section (RAM and other data memory), and creates a
symbol indicating its top address with the specified name. By using this symbol, you can describe an
instruction to access the RAM.
symbol indicating its top address with the specified name. By using this symbol, you can describe an
instruction to access the RAM.
Difference between .comm and .lcomm
The .comm pseudo-instruction and the .lcomm pseudo-instruction are exactly the same in function,
but they do differ from each other in the scope of the symbols they create. The symbols created by the
.comm
but they do differ from each other in the scope of the symbols they create. The symbols created by the
.comm
pseudo-instruction become global symbols, which can be referred to externally from other
modules (however, the file to be referred to needs to be specified by the .global pseudo-instruction).
The symbols created by the .lcomm pseudo-instruction are local symbols, which cannot be referred to
from other modules.
The symbols created by the .lcomm pseudo-instruction are local symbols, which cannot be referred to
from other modules.
Precaution
The .comm and .lcomm pseudo-instructions can only be described in BSS sections.