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typo found by Katie

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Perry Kivolowitz 2023-02-23 14:06:35 -06:00
parent e7a99b1072
commit 372a2598f5
2 changed files with 22 additions and 16 deletions
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38
section_1/regs/widths.md
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@ -67,13 +67,18 @@ ram: .quad 0xFFFFFFFFFFFFFFFF // 14
// 17
```
`Line 14` puts an identifiable pattern into 8 bytes of RAM and gives them the symbol `ram`.
`Line 14` puts an identifiable pattern into 8 bytes of RAM and gives
them the symbol `ram`.
`Line 6` gets the address of these bytes into `x1`.
The next four lines put zeros into that memory using progressively wider store instructions.
The next four lines put zeros into that memory using progressively wider
store instructions.
The following is a `gdb` session running the above program. Line numbers have been added to assist with the description of the session. Rather than describe all after a wall of text, descriptions will be provided inline.
The following is a `gdb` session running the above program. Line numbers
have been added to assist with the description of the session. Rather
than describe all after a wall of text, descriptions will be provided
inline.
```text
(gdb) b main // 1
@ -164,7 +169,8 @@ Adding the `g` (for `g`iant) we can see all 8 bytes.
0xaaaaaaab1010: 0xffffffffffffff00 // 29
```
We just did a `strb` and looking at memory, we see one byte's worth of zeros.
We just did a `strb` and looking at memory, we see one byte's worth of
zeros.
*Note: this brings up an interesting question... which byte is actually
sitting at the address of `ram`? We will have to look into this more
@ -203,8 +209,8 @@ the address `ram`? When we examined the `long` just after putting in one
byte of zero, we saw this:
```text
(gdb) x/gx &ram // 28
0xaaaaaaab1010: 0xffffffffffffff00 // 29
(gdb) x/gx &ram // 28
0xaaaaaaab1010: 0xffffffffffffff00 // 29
```
Notice the zeros come at the end. Keep in mind, these bytes are printed
@ -233,16 +239,16 @@ Given this program (not intended for meaningful execution... just
e`x`amining memory):
```asm
.global main // 1
.text // 2
.align 2 // 3
// 4
main: mov x0, xzr // 5
ret // 6
// 7
.data // 8
ram: .quad 0xAABBCCDDEEFF0011 // 9
.end // 10
.global main // 1
.text // 2
.align 2 // 3
// 4
main: mov x0, xzr // 5
ret // 6
// 7
.data // 8
ram: .quad 0xAABBCCDDEEFF0011 // 9
.end // 10
```
let's take a look at the memory at location `ram` in two ways. Once

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section_1/regs/widths.pdf
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