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Improve bit rotation/shift explanations by using Unicode box diagrams

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The existing explanations have proven confusing to many,
and presenting the instructions in a more visual manner should help a lot.

Additionally, the Unicode codepoints are typed as-is in the source,
because that allows much more WYSIWYG editing, and god damn it this is the year
two thousand and twenty three, if your man and/or terminal software does't
support Unicode, then what are you *doing*.
This commit is contained in:
ISSOtm
2023-06-17 12:38:31 +02:00
parent a0dfa916e6
commit 6d806238fb
1 changed files with 112 additions and 26 deletions
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138
man/gbz80.7
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@@ -1321,9 +1321,14 @@ Flags: None affected.
.Ss RL r8
Rotate bits in register
.Ar r8
left through carry.
left, through the carry flag.
.Pp
.D1 C <- [7 <- 0] <- C
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━━ r8 ━━━━━━┓
┌─╂─ C ←╂─╂─ b7 ← ... ← b0 ←╂─┐
│ ┗━━━━━━━━━┛ ┗━━━━━━━━━━━━━━━━━┛ │
└─────────────────────────────────┘
.Ed
.Pp
Cycles: 2
.Pp
@@ -1343,9 +1348,14 @@ Set according to result.
.Ss RL [HL]
Rotate the byte pointed to by
.Sy HL
left through carry.
left, through the carry flag.
.Pp
.D1 C <- [7 <- 0] <- C
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━ [HL] ━━━━━┓
┌─╂─ C ←╂─╂─ b7 ← ... ← b0 ←╂─┐
│ ┗━━━━━━━━━┛ ┗━━━━━━━━━━━━━━━━━┛ │
└─────────────────────────────────┘
.Ed
.Pp
Cycles: 4
.Pp
@@ -1356,9 +1366,14 @@ Flags: See
.Ss RLA
Rotate register
.Sy A
left through carry.
left, through the carry flag.
.Pp
.D1 C <- [7 <- 0] <- C
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━━ A ━━━━━━━┓
┌─╂─ C ←╂─╂─ b7 ← ... ← b0 ←╂─┐
│ ┗━━━━━━━━━┛ ┗━━━━━━━━━━━━━━━━━┛ │
└─────────────────────────────────┘
.Ed
.Pp
Cycles: 1
.Pp
@@ -1380,7 +1395,12 @@ Rotate register
.Ar r8
left.
.Pp
.D1 C <- [7 <- 0] <- [7]
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━━ r8 ━━━━━━┓
┃ C ←╂─┬─╂─ b7 ← ... ← b0 ←╂─┐
┗━━━━━━━━━┛ │ ┗━━━━━━━━━━━━━━━━━┛ │
└─────────────────────┘
.Ed
.Pp
Cycles: 2
.Pp
@@ -1402,7 +1422,12 @@ Rotate the byte pointed to by
.Sy HL
left.
.Pp
.D1 C <- [7 <- 0] <- [7]
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━ [HL] ━━━━━┓
┃ C ←╂─┬─╂─ b7 ← ... ← b0 ←╂─┐
┗━━━━━━━━━┛ │ ┗━━━━━━━━━━━━━━━━━┛ │
└─────────────────────┘
.Ed
.Pp
Cycles: 4
.Pp
@@ -1415,7 +1440,12 @@ Rotate register
.Sy A
left.
.Pp
.D1 C <- [7 <- 0] <- [7]
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━━ A ━━━━━━━┓
┃ C ←╂─┬─╂─ b7 ← ... ← b0 ←╂─┐
┗━━━━━━━━━┛ │ ┗━━━━━━━━━━━━━━━━━┛ │
└─────────────────────┘
.Ed
.Pp
Cycles: 1
.Pp
@@ -1435,9 +1465,14 @@ Set according to result.
.Ss RR r8
Rotate register
.Ar r8
right through carry.
right, through the carry flag.
.Pp
.D1 C -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━━ r8 ━━━━━━┓ ┏━ Flags ━┓
┌─╂→ b7 → ... → b0 ─╂─╂→ C ─╂─┐
│ ┗━━━━━━━━━━━━━━━━━┛ ┗━━━━━━━━━┛ │
└─────────────────────────────────┘
.Ed
.Pp
Cycles: 2
.Pp
@@ -1457,9 +1492,14 @@ Set according to result.
.Ss RR [HL]
Rotate the byte pointed to by
.Sy HL
right through carry.
right, through the carry flag.
.Pp
.D1 C -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━ [HL] ━━━━━┓ ┏━ Flags ━┓
┌─╂→ b7 → ... → b0 ─╂─╂→ C ─╂─┐
│ ┗━━━━━━━━━━━━━━━━━┛ ┗━━━━━━━━━┛ │
└─────────────────────────────────┘
.Ed
.Pp
Cycles: 4
.Pp
@@ -1470,9 +1510,14 @@ Flags: See
.Ss RRA
Rotate register
.Sy A
right through carry.
right, through the carry flag.
.Pp
.D1 C -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━━ A ━━━━━━━┓ ┏━ Flags ━┓
┌─╂→ b7 → ... → b0 ─╂─╂→ C ─╂─┐
│ ┗━━━━━━━━━━━━━━━━━┛ ┗━━━━━━━━━┛ │
└─────────────────────────────────┘
.Ed
.Pp
Cycles: 1
.Pp
@@ -1494,7 +1539,12 @@ Rotate register
.Ar r8
right.
.Pp
.D1 [0] -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━━ r8 ━━━━━━┓ ┏━ Flags ━┓
┌─╂→ b7 → ... → b0 ─╂─┬─╂→ C ┃
│ ┗━━━━━━━━━━━━━━━━━┛ │ ┗━━━━━━━━━┛
└─────────────────────┘
.Ed
.Pp
Cycles: 2
.Pp
@@ -1516,7 +1566,12 @@ Rotate the byte pointed to by
.Sy HL
right.
.Pp
.D1 [0] -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━ [HL] ━━━━━┓ ┏━ Flags ━┓
┌─╂→ b7 → ... → b0 ─╂─┬─╂→ C ┃
│ ┗━━━━━━━━━━━━━━━━━┛ │ ┗━━━━━━━━━┛
└─────────────────────┘
.Ed
.Pp
Cycles: 4
.Pp
@@ -1529,7 +1584,12 @@ Rotate register
.Sy A
right.
.Pp
.D1 [0] -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━━ A ━━━━━━━┓ ┏━ Flags ━┓
┌─╂→ b7 → ... → b0 ─╂─┬─╂→ C ┃
│ ┗━━━━━━━━━━━━━━━━━┛ │ ┗━━━━━━━━━┛
└─────────────────────┘
.Ed
.Pp
Cycles: 1
.Pp
@@ -1654,7 +1714,11 @@ Flags: None affected.
Shift Left Arithmetically register
.Ar r8 .
.Pp
.D1 C <- [7 <- 0] <- 0
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━━ r8 ━━━━━━┓
┃ C ←╂─╂─ b7 ← ... ← b0 ←╂─ 0
┗━━━━━━━━━┛ ┗━━━━━━━━━━━━━━━━━┛
.Ed
.Pp
Cycles: 2
.Pp
@@ -1675,7 +1739,11 @@ Set according to result.
Shift Left Arithmetically the byte pointed to by
.Sy HL .
.Pp
.D1 C <- [7 <- 0] <- 0
.Bd -literal
┏━ Flags ━┓ ┏━━━━━━ [HL] ━━━━━┓
┃ C ←╂─╂─ b7 ← ... ← b0 ←╂─ 0
┗━━━━━━━━━┛ ┗━━━━━━━━━━━━━━━━━┛
.Ed
.Pp
Cycles: 4
.Pp
@@ -1685,9 +1753,14 @@ Flags: See
.Sx SLA r8
.Ss SRA r8
Shift Right Arithmetically register
.Ar r8 .
.Ar r8
.Pq bit 7 of Ar r8 No is unchanged .
.Pp
.D1 [7] -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━ r8 ━━━━━━┓ ┏━ Flags ━┓
┃ b7 → ... → b0 ─╂─╂→ C ┃
┗━━━━━━━━━━━━━━━━┛ ┗━━━━━━━━━┛
.Ed
.Pp
Cycles: 2
.Pp
@@ -1706,9 +1779,14 @@ Set according to result.
.El
.Ss SRA [HL]
Shift Right Arithmetically the byte pointed to by
.Sy HL .
.Sy HL
.Pq bit 7 of the byte pointed to by Sy HL No is unchanged .
.Pp
.D1 [7] -> [7 -> 0] -> C
.Bd -literal
┏━━━━━ [HL] ━━━━━┓ ┏━ Flags ━┓
┃ b7 → ... → b0 ─╂─╂→ C ┃
┗━━━━━━━━━━━━━━━━┛ ┗━━━━━━━━━┛
.Ed
.Pp
Cycles: 4
.Pp
@@ -1720,7 +1798,11 @@ Flags: See
Shift Right Logically register
.Ar r8 .
.Pp
.D1 0 -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━━ r8 ━━━━━━┓ ┏━ Flags ━┓
0 ─╂→ b7 → ... → b0 ─╂─╂→ C ┃
┗━━━━━━━━━━━━━━━━━┛ ┗━━━━━━━━━┛
.Ed
.Pp
Cycles: 2
.Pp
@@ -1741,7 +1823,11 @@ Set according to result.
Shift Right Logically the byte pointed to by
.Sy HL .
.Pp
.D1 0 -> [7 -> 0] -> C
.Bd -literal
┏━━━━━━ [HL] ━━━━━┓ ┏━ Flags ━┓
0 ─╂→ b7 → ... → b0 ─╂─╂→ C ┃
┗━━━━━━━━━━━━━━━━━┛ ┗━━━━━━━━━┛
.Ed
.Pp
Cycles: 4
.Pp