s3c2410a Samsung Semiconductor, Inc., s3c2410a Datasheet - Page 169

• Manufacturer Part Number: s3c2410a
• Description: 16/32-bit Risc Arm Microprocessor
• Manufacturer: Samsung Semiconductor, Inc.

S3C2410A
OPERATION
These instructions transfer byte or word values between registers and memory using an immediate 5 or 7-bit offset.
The THUMB assembler syntax is shown in Table 4-10.
NOTE:
INSTRUCTION CYCLE TIMES
All instructions in this format have an equivalent ARM instruction as shown in Table 4-10. The instruction cycle times
for the THUMB instruction are identical to that of the equivalent ARM instruction.
EXAMPLES
L
0
1
0
1
For word accesses (B = 0), the value specified by #Imm is a full 7-bit address, but must be word-aligned
(ie with bits 1:0 set to 0), since the assembler places #Imm >> 2 in the Offset5 field.
B
0
0
1
1
LDR
STRB
STR Rd, [Rb, #Imm]
LDR Rd, [Rb, #Imm]
STRB Rd, [Rb, #Imm]
LDRB Rd, [Rb, #Imm]
THUMB assembler
R2, [R5,#116]
R1, [R0,#13]
Table 4-10. Summary of Format 9 Instructions
STR Rd, [Rb, #Imm]
LDR Rd, [Rb, #Imm]
STRB Rd, [Rb, #Imm]
LDRB Rd, [Rb, #Imm]
ARM equivalent
; Load into R2 the word found at the
; address formed by adding 116 to R5.
; Note that the THUMB opcode will
; contain 29 as the Offset5 value.
; Store the lower 8 bits of R1 at the
; address formed by adding 13 to R0.
; Note that the THUMB opcode will
; contain 13 as the Offset5 value.
Calculate the target address by adding
together the value in Rb and Imm. Store
the contents of Rd at the address.
Calculate the source address by adding
together the value in Rb and Imm. Load
Rd from the address.
Calculate the target address by adding
together the value in Rb and Imm. Store
the byte value in Rd at the address.
Calculate source address by adding
together the value in Rb and Imm. Load
the byte value at the address into Rd.
Action
THUMB INSTRUCTION SET
4-23