S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X ADDRESS SPACES
2-5
REGISTER ARCHITECTURE
In the S3C8275X/C8278X/C8274X implementation, the upper 64-byte area of register files is expanded two
64-byte areas, called set 1 and set 2. The upper 32-byte area of set 1 is further expanded two 32-byte register
banks (bank 0 and bank 1), and the lower 32-byte area is a single 32-byte common area.
In case of S3C8275X the total number of addressable 8-bit registers is 605. Of these 605 registers, 13 bytes are
for CPU and system control registers, 16 bytes are for LCD data registers, 48 bytes are for peripheral control and
data registers, 16 bytes are used as a shared working registers, and 512 registers are for general-purpose use,
page 0-page 1 (in case of S3C8278X/C8274X, page 0).
You can always address set 1 register locations, regardless of which of the two register pages is currently
selected. Set 1 locations, however, can only be addressed using register addressing modes.
The extension of register space into separately addressable areas (sets, banks, and pages) is supported by
various addressing mode restrictions, the select bank instructions, SB0 and SB1, and the register page pointer
(PP).
Specific register types and the area (in bytes) that they occupy in the register file are summarized in Table 2-1.
Table 2-1. S3C8275X Register Type Summary
Register Type Number of Bytes
General-purpose registers (including the 16-byte
common working register area, two 192-byte prime
register area, and two 64-byte set 2 area)
LCD data registers
CPU and system control registers
Mapped clock, peripheral, I/O control, and data registers
528
16
13
48
Total Addressable Bytes 605
Table 2-2. S3C8278X/C8274X Register Type Summary
Register Type Number of Bytes
General-purpose registers (including the 16-byte
common working register area, one 192-byte prime
register area, and one 64-byte set 2 area)
LCD data registers
CPU and system control registers
Mapped clock, peripheral, I/O control, and data registers
272
16
13
48
Total Addressable Bytes 349