diff options
| author | Andrew Waterman <andrew@sifive.com> | 2023-10-06 16:31:54 -0700 |
|---|---|---|
| committer | Andrew Waterman <andrew@sifive.com> | 2023-10-06 16:42:17 -0700 |
| commit | f98344f3e7db9e340c466b4b93972b43f08c3ca1 (patch) | |
| tree | a79d8845f20ee6dd4410660e6dca7bc11ebbf646 /src/zimop.adoc | |
| parent | d924944fa58d21547ee72fd3fec6020ef2f3337c (diff) | |
| download | riscv-isa-manual-f98344f3e7db9e340c466b4b93972b43f08c3ca1.zip riscv-isa-manual-f98344f3e7db9e340c466b4b93972b43f08c3ca1.tar.gz riscv-isa-manual-f98344f3e7db9e340c466b4b93972b43f08c3ca1.tar.bz2 | |
Number c.mop instructions more intuitively
h/t @jhauser-us
Diffstat (limited to 'src/zimop.adoc')
| -rw-r--r-- | src/zimop.adoc | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/src/zimop.adoc b/src/zimop.adoc index 0b4db59..32f0841 100644 --- a/src/zimop.adoc +++ b/src/zimop.adoc @@ -63,14 +63,14 @@ implementations of reading `x[rs1]` and `x[rs2]`. === "Zcmop" Compressed May-Be-Operations Extension, Version 0.1 This section defines the "Zcmop" extension, which defines eight 16-bit MOP -instructions named `c.mop.__n__`, where __n__ is an integer between 0 and 7, -inclusive. `c.mop.__n__` is encoded in the reserved encoding space -corresponding to `c.lui x__m__, 0`, where __m__=2__n__+1, as shown in Table +instructions named `c.mop.__n__`, where __n__ is an odd integer between 1 and +15, inclusive. `c.mop.__n__` is encoded in the reserved encoding space +corresponding to `c.lui x__n__, 0`, as shown in Table <<tab:c-mop>>. Unlike the MOPs defined in the Zimop extension, the `c.mop.__n__` instructions are defined to _not_ write any register. Their encoding allows future extensions to define them to read register -`x[__m__]`. +`x[__n__]`. include::images/wavedrom/c-mop.adoc[] [[c-mop]] @@ -86,18 +86,18 @@ therefore of lower value for most purposes. |=== |Mnemonic | Encoding | Redefinable to read register -|c.mop.0 | `0110000010000001` | `x1` -|c.mop.1 | `0110000110000001` | `x3` -|c.mop.2 | `0110001010000001` | `x5` -|c.mop.3 | `0110001110000001` | `x7` -|c.mop.4 | `0110010010000001` | `x9` -|c.mop.5 | `0110010110000001` | `x11` -|c.mop.6 | `0110011010000001` | `x13` -|c.mop.7 | `0110011110000001` | `x15` +|c.mop.1 | `0110000010000001` | `x1` +|c.mop.3 | `0110000110000001` | `x3` +|c.mop.5 | `0110001010000001` | `x5` +|c.mop.7 | `0110001110000001` | `x7` +|c.mop.9 | `0110010010000001` | `x9` +|c.mop.11 | `0110010110000001` | `x11` +|c.mop.13 | `0110011010000001` | `x13` +|c.mop.15 | `0110011110000001` | `x15` |=== NOTE: The recommended assembly syntax for `c.mop.__n__` is simply the nullary -`c.mop.__n__`. The possibly accessed register is implicitly `x__m__`. +`c.mop.__n__`. The possibly accessed register is implicitly `x__n__`. NOTE: The expectation is that each Zcmop instruction is equivalent to some Zimop instruction, but the choice of expansion (if any) is left to the |