pan/midgard/disasm: Fix printing 8-bit/16-bit masks

The trick is realizing even with a destination override, the masks are encoded in the same mode as the
instruction itself, rather than stepping down. The override means that
the smaller type is used, but the mask is parsed as if it were the
higher type. Overriding down is down by printed by blinding doing this. Overriding up can be thought of as printing in the upper size, but shifting the alphabet to use the upper half, i.e. shifting xyzw to become abcd.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>

diff --git a/src/panfrost/midgard/disassemble.c b/src/panfrost/midgard/disassemble.c
index df637a3ef5971063d8b572077b96b72560ca0af8..7680d037937cb01a02ceac7856c6748d37e179c6 100644 (file)
--- a/src/panfrost/midgard/disassemble.c
+++ b/src/panfrost/midgard/disassemble.c
@@ -401,7 +401,7 @@ update_dest(unsigned reg)
         }
 }
 
-static unsigned
+static void
 print_dest(unsigned reg, midgard_reg_mode mode, midgard_dest_override override)
 {
         /* Depending on the mode and override, we determine the type of
@@ -415,8 +415,6 @@ print_dest(unsigned reg, midgard_reg_mode mode, midgard_dest_override override)
 
         update_dest(reg);
         print_reg(reg, bits);
-
-        return bits;
 }
 
 static void
@@ -424,20 +422,11 @@ print_mask_vec16(uint8_t mask, midgard_dest_override override)
 {
         printf(".");
 
-        if (override == midgard_dest_override_none) {
-                for (unsigned i = 0; i < 8; i++) {
-                        if (mask & (1 << i))
-                                printf("%c%c",
-                                       components[i*2 + 0],
-                                       components[i*2 + 1]);
-                }
-        } else {
-                bool upper = (override == midgard_dest_override_upper);
-
-                for (unsigned i = 0; i < 8; i++) {
-                        if (mask & (1 << i))
-                                printf("%c", components[i + (upper ? 8 : 0)]);
-                }
+        for (unsigned i = 0; i < 8; i++) {
+                if (mask & (1 << i))
+                        printf("%c%c",
+                               components[i*2 + 0],
+                               components[i*2 + 1]);
         }
 }
 
@@ -456,24 +445,18 @@ print_mask(uint8_t mask, unsigned bits, midgard_dest_override override)
                 return;
         }
 
-        if (bits < 16) {
-                /* Shouldn't happen but with junk / out-of-spec shaders it
-                 * would cause an infinite loop */
-
-                printf("/* XXX: bits = %u */", bits);
-                return;
-        }
-
         /* Skip 'complete' masks */
 
-        if (bits >= 32 && mask == 0xFF) return;
-
-        if (bits == 16) {
-                if (mask == 0x0F)
-                        return;
-                else if (mask == 0xF0) {
-                        printf("'");
-                        return;
+        if (override == midgard_dest_override_none) {
+                if (bits >= 32 && mask == 0xFF) return;
+
+                if (bits == 16) {
+                        if (mask == 0x0F)
+                                return;
+                        else if (mask == 0xF0) {
+                                printf("'");
+                                return;
+                        }
                 }
         }
 
@@ -483,6 +466,17 @@ print_mask(uint8_t mask, unsigned bits, midgard_dest_override override)
         bool uppercase = bits > 32;
         bool tripped = false;
 
+        /* To apply an upper destination override, we "shift" the alphabet.
+         * E.g. with an upper override on 32-bit, instead of xyzw, print efgh.
+         * For upper 16-bit, instead of xyzwefgh, print ijklmnop */
+
+        const char *alphabet = components;
+
+        if (override == midgard_dest_override_upper) {
+                unsigned components = 128 / bits;
+                alphabet += components;
+        }
+
         for (unsigned i = 0; i < 8; i += skip) {
                 bool a = (mask & (1 << i)) != 0;
 
@@ -492,7 +486,7 @@ print_mask(uint8_t mask, unsigned bits, midgard_dest_override override)
                 }
 
                 if (a) {
-                        char c = components[i / skip];
+                        char c = alphabet[i / skip];
 
                         if (uppercase)
                                 c = toupper(c);
@@ -554,20 +548,7 @@ print_vector_field(const char *name, uint16_t *words, uint16_t reg_word,
         uint8_t mask = alu_field->mask;
 
         /* First, print the destination */
-        unsigned dest_size =
-                print_dest(reg_info->out_reg, mode, alu_field->dest_override);
-
-        /* Apply the destination override to the mask */
-
-        if (mode == midgard_reg_mode_32 || mode == midgard_reg_mode_64) {
-                if (override == midgard_dest_override_lower)
-                        mask &= 0x0F;
-                else if (override == midgard_dest_override_upper)
-                        mask &= 0xF0;
-        } else if (mode == midgard_reg_mode_16
-                   && override == midgard_dest_override_lower) {
-                /* stub */
-        }
+        print_dest(reg_info->out_reg, mode, alu_field->dest_override);
 
         if (override != midgard_dest_override_none) {
                 bool modeable = (mode != midgard_reg_mode_8);
@@ -577,7 +558,7 @@ print_vector_field(const char *name, uint16_t *words, uint16_t reg_word,
                         printf("/* do%u */ ", override);
         }
 
-        print_mask(mask, dest_size, override);
+        print_mask(mask, bits_for_mode(mode), override);
 
         printf(", ");