The ARMulator (as the ARM chips) as signal, if a seqeuntial or non-sequential
memory access is requested. I found a strange behavior in armulator
The program basically writes a string (hello world) to the console:
HelloW
+0000 0x00008080: 0xe28f1010 .... : add r1,pc,#0x10
LOOP
+0000 0x00008084: 0xe4d10001 .... : ldrb r0,[r1],#1
+0004 0x00008088: 0xe3500000 ..P. : cmp r0,#0
+0008 0x0000808c: 0x1f000000 .... : swine 0x0
+000c 0x00008090: 0x1afffffb .... : bne LOOP
+0010 0x00008094: 0xef000011 .... : > swi 0x11
Text
+0000 0x00008098: 0x6c6c6548 Hell : stcvsl p5,c6,[r12],#-0x120
+0004 0x0000809c: 0x6f57206f o Wo : swivs 0x57206f
+0008 0x000080a0: 0x0a646c72 rld. : beq 0x1923270
The address trace of this part is given below. The Load Byte is called delayed
due to the pipeline (as the reading of 8094 and 8098. But the strange thing is
that the instruction after the ldrb is a sequential cycle (8090). Does anybody
know why is this? Thanks.
00008084 (Load Instruction - non-sequential cycle)
00008088 (Load Instruction - sequential cycle)
0000808C (Load Instruction - sequential cycle)
000080A3 (Load Byte - non - sequential cycle)
00008090 (Load Instruction - sequential cycle)
00008094 (Load Instruction - sequential cycle)
00008098 (Load Instruction - sequential cycle)
00008084 (Load Instruction - non-sequential cycle)
00008088 (Load Instruction - sequential cycle)
0000808C (Load Instruction - sequential cycle)
000080A4 (Load Byte - non - sequential cycle)
00008090 (Load Instruction - sequential cycle)
00008094 (Load Instruction - sequential cycle)
00008098 (Load Instruction - sequential cycle)
00008084 (Load Instruction - non-sequential cycle)
00008088 (Load Instruction - sequential cycle)
0000808C (Load Instruction - sequential cycle)
000080A5 (Load Byte - non - sequential cycle)
00008090 (Load Instruction - sequential cycle)
00008094 (Load Instruction - sequential cycle)
00008098 (Load Instruction - sequential cycle)
0000809C (Load Instruction - sequential cycle)
--
Rainer Dorsch
Abt. Rechnerarchitektur e-mail:[EMAIL PROTECTED]
Uni Stuttgart Tel.: 0711-7816-215
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