linux-kernel - [PATCH 10/36] tty/vt: consolemap: introduce UNI

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Date:   Tue,  7 Jun 2022 12:49:20 +0200
From:   Jiri Slaby <jslaby@...e.cz>
To:     gregkh@...uxfoundation.org
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 10/36] tty/vt: consolemap: introduce UNI_*() macros

The code currently does shift, OR, and AND logic directly in the code.
It is not much obvious what happens there. Therefore define four macros
for that purpose and use them in the code. We use GENMASK() so that it
is clear which bits serve what purpose:
- UNI_GLYPH: bits  0.. 5
- UNI_ROW:   bits  6..10
- UNI_DIR:   bits 11..31

Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 drivers/tty/vt/consolemap.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 016c1a0b4290..e5fd225e87bd 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -190,6 +190,11 @@ static int inv_translate[MAX_NR_CONSOLES];
 #define UNI_DIR_ROWS	32U
 #define UNI_ROW_GLYPHS	64U
 
+#define UNI_DIR(uni)		( (uni)                   >> 11)
+#define UNI_ROW(uni)		(((uni) & GENMASK(10, 6)) >>  6)
+#define UNI_GLYPH(uni)		( (uni) & GENMASK( 5, 0))
+#define UNI(dir, row, glyph)	(((dir) << 11) | ((row) << 6) | (glyph))
+
 /**
  * struct uni_pagedict -- unicode directory
  *
@@ -265,7 +270,7 @@ static void set_inverse_trans_unicode(struct vc_data *conp,
 				glyph = p2[k];
 				if (glyph >= 0 && glyph < MAX_GLYPH
 					       && q[glyph] < 32)
-					q[glyph] = (i << 11) | (j << 6) | k;
+					q[glyph] = UNI(i, j, k);
 			}
 		}
 	}
@@ -497,7 +502,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
 	int i, n;
 	u16 **p1, *p2;
 
-	n = unicode >> 11;
+	n = UNI_DIR(unicode);
 	p1 = p->uni_pgdir[n];
 	if (!p1) {
 		p1 = p->uni_pgdir[n] = kmalloc_array(UNI_DIR_ROWS,
@@ -508,7 +513,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
 			p1[i] = NULL;
 	}
 
-	n = (unicode >> 6) & 0x1f;
+	n = UNI_ROW(unicode);
 	p2 = p1[n];
 	if (!p2) {
 		p2 = p1[n] = kmalloc_array(UNI_ROW_GLYPHS, sizeof(u16), GFP_KERNEL);
@@ -518,7 +523,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
 		memset(p2, 0xff, UNI_ROW_GLYPHS * sizeof(u16));
 	}
 
-	p2[unicode & 0x3f] = fontpos;
+	p2[UNI_GLYPH(unicode)] = fontpos;
 	
 	p->sum += (fontpos << 20U) + unicode;
 
@@ -788,7 +793,7 @@ int con_get_unimap(struct vc_data *vc, ushort ct, ushort __user *uct, struct uni
 						continue;
 					if (ect < ct) {
 						unilist[ect].unicode =
-							(i<<11) | (j<<6) | k;
+							UNI(i, j, k);
 						unilist[ect].fontpos = *p2;
 					}
 					ect++;
@@ -857,9 +862,9 @@ conv_uni_to_pc(struct vc_data *conp, long ucs)
 		return -3;
 
 	p = *conp->vc_uni_pagedir_loc;
-	if ((p1 = p->uni_pgdir[ucs >> 11]) &&
-	    (p2 = p1[(ucs >> 6) & 0x1f]) &&
-	    (h = p2[ucs & 0x3f]) < MAX_GLYPH)
+	if ((p1 = p->uni_pgdir[UNI_DIR(ucs)]) &&
+	    (p2 = p1[UNI_ROW(ucs)]) &&
+	    (h = p2[UNI_GLYPH(ucs)]) < MAX_GLYPH)
 		return h;
 
 	return -4;		/* not found */
-- 
2.36.1