The next patch will reuse latched memory access in text modes. Start with
a patch that moves the latched access code out of the "if".
Best reviewed with "git diff -b".
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/display/vga.c | 211 ++++++++++++++++++++++++-----------------------
1 file changed, 110 insertions(+), 101 deletions(-)
diff --git a/hw/display/vga.c b/hw/display/vga.c
index 2467f3f6c65..08ba5bb1118 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -832,37 +832,41 @@ uint32_t vga_mem_readb(VGACommonState *s, hwaddr addr)
}
if (sr(s, VGA_SEQ_MEMORY_MODE) & VGA_SR04_CHN_4M) {
- /* chain 4 mode : simplest access */
+ /* chain 4 mode : simplest access (but it should use the same
+ * algorithms as below; see e.g. vga_mem_writeb's plane mask check).
+ */
assert(addr < s->vram_size);
- ret = s->vram_ptr[addr];
- } else if (s->gr[VGA_GFX_MODE] & 0x10) {
+ return s->vram_ptr[addr];
+ }
+
+ if (s->gr[VGA_GFX_MODE] & 0x10) {
/* odd/even mode (aka text mode mapping) */
plane = (s->gr[VGA_GFX_PLANE_READ] & 2) | (addr & 1);
addr = ((addr & ~1) << 1) | plane;
if (addr >= s->vram_size) {
return 0xff;
}
- ret = s->vram_ptr[addr];
- } else {
- /* standard VGA latched access */
- if (addr * sizeof(uint32_t) >= s->vram_size) {
- return 0xff;
- }
- s->latch = ((uint32_t *)s->vram_ptr)[addr];
-
- if (!(s->gr[VGA_GFX_MODE] & 0x08)) {
- /* read mode 0 */
- plane = s->gr[VGA_GFX_PLANE_READ];
- ret = GET_PLANE(s->latch, plane);
- } else {
- /* read mode 1 */
- ret = (s->latch ^ mask16[s->gr[VGA_GFX_COMPARE_VALUE]]) &
- mask16[s->gr[VGA_GFX_COMPARE_MASK]];
- ret |= ret >> 16;
- ret |= ret >> 8;
- ret = (~ret) & 0xff;
- }
+ return s->vram_ptr[addr];
}
+
+ /* standard VGA latched access */
+ plane = s->gr[VGA_GFX_PLANE_READ];
+ if (addr * sizeof(uint32_t) >= s->vram_size) {
+ return 0xff;
+ }
+ s->latch = ((uint32_t *)s->vram_ptr)[addr];
+ if (!(s->gr[VGA_GFX_MODE] & 0x08)) {
+ /* read mode 0 */
+ ret = GET_PLANE(s->latch, plane);
+ } else {
+ /* read mode 1 */
+ ret = (s->latch ^ mask16[s->gr[VGA_GFX_COMPARE_VALUE]]) &
+ mask16[s->gr[VGA_GFX_COMPARE_MASK]];
+ ret |= ret >> 16;
+ ret |= ret >> 8;
+ ret = (~ret) & 0xff;
+ }
+
return ret;
}
@@ -912,7 +916,10 @@ void vga_mem_writeb(VGACommonState *s, hwaddr addr, uint32_t val)
s->plane_updated |= mask; /* only used to detect font change */
memory_region_set_dirty(&s->vram, addr, 1);
}
- } else if (s->gr[VGA_GFX_MODE] & 0x10) {
+ return;
+ }
+
+ if (s->gr[VGA_GFX_MODE] & 0x10) {
/* odd/even mode (aka text mode mapping) */
plane = (s->gr[VGA_GFX_PLANE_READ] & 2) | (addr & 1);
mask = (1 << plane);
@@ -928,84 +935,86 @@ void vga_mem_writeb(VGACommonState *s, hwaddr addr, uint32_t val)
s->plane_updated |= mask; /* only used to detect font change */
memory_region_set_dirty(&s->vram, addr, 1);
}
- } else {
- /* standard VGA latched access */
- write_mode = s->gr[VGA_GFX_MODE] & 3;
- switch(write_mode) {
- default:
- case 0:
- /* rotate */
- b = s->gr[VGA_GFX_DATA_ROTATE] & 7;
- val = ((val >> b) | (val << (8 - b))) & 0xff;
- val |= val << 8;
- val |= val << 16;
-
- /* apply set/reset mask */
- set_mask = mask16[s->gr[VGA_GFX_SR_ENABLE]];
- val = (val & ~set_mask) |
- (mask16[s->gr[VGA_GFX_SR_VALUE]] & set_mask);
- bit_mask = s->gr[VGA_GFX_BIT_MASK];
- break;
- case 1:
- val = s->latch;
- goto do_write;
- case 2:
- val = mask16[val & 0x0f];
- bit_mask = s->gr[VGA_GFX_BIT_MASK];
- break;
- case 3:
- /* rotate */
- b = s->gr[VGA_GFX_DATA_ROTATE] & 7;
- val = (val >> b) | (val << (8 - b));
-
- bit_mask = s->gr[VGA_GFX_BIT_MASK] & val;
- val = mask16[s->gr[VGA_GFX_SR_VALUE]];
- break;
- }
-
- /* apply logical operation */
- func_select = s->gr[VGA_GFX_DATA_ROTATE] >> 3;
- switch(func_select) {
- case 0:
- default:
- /* nothing to do */
- break;
- case 1:
- /* and */
- val &= s->latch;
- break;
- case 2:
- /* or */
- val |= s->latch;
- break;
- case 3:
- /* xor */
- val ^= s->latch;
- break;
- }
-
- /* apply bit mask */
- bit_mask |= bit_mask << 8;
- bit_mask |= bit_mask << 16;
- val = (val & bit_mask) | (s->latch & ~bit_mask);
-
- do_write:
- /* mask data according to sr[2] */
- mask = sr(s, VGA_SEQ_PLANE_WRITE);
- s->plane_updated |= mask; /* only used to detect font change */
- write_mask = mask16[mask];
- if (addr * sizeof(uint32_t) >= s->vram_size) {
- return;
- }
- ((uint32_t *)s->vram_ptr)[addr] =
- (((uint32_t *)s->vram_ptr)[addr] & ~write_mask) |
- (val & write_mask);
-#ifdef DEBUG_VGA_MEM
- printf("vga: latch: [0x" HWADDR_FMT_plx "] mask=0x%08x val=0x%08x\n",
- addr * 4, write_mask, val);
-#endif
- memory_region_set_dirty(&s->vram, addr << 2, sizeof(uint32_t));
+ return;
}
+
+ mask = sr(s, VGA_SEQ_PLANE_WRITE);
+
+ /* standard VGA latched access */
+ write_mode = s->gr[VGA_GFX_MODE] & 3;
+ switch(write_mode) {
+ default:
+ case 0:
+ /* rotate */
+ b = s->gr[VGA_GFX_DATA_ROTATE] & 7;
+ val = ((val >> b) | (val << (8 - b))) & 0xff;
+ val |= val << 8;
+ val |= val << 16;
+
+ /* apply set/reset mask */
+ set_mask = mask16[s->gr[VGA_GFX_SR_ENABLE]];
+ val = (val & ~set_mask) |
+ (mask16[s->gr[VGA_GFX_SR_VALUE]] & set_mask);
+ bit_mask = s->gr[VGA_GFX_BIT_MASK];
+ break;
+ case 1:
+ val = s->latch;
+ goto do_write;
+ case 2:
+ val = mask16[val & 0x0f];
+ bit_mask = s->gr[VGA_GFX_BIT_MASK];
+ break;
+ case 3:
+ /* rotate */
+ b = s->gr[VGA_GFX_DATA_ROTATE] & 7;
+ val = (val >> b) | (val << (8 - b));
+
+ bit_mask = s->gr[VGA_GFX_BIT_MASK] & val;
+ val = mask16[s->gr[VGA_GFX_SR_VALUE]];
+ break;
+ }
+
+ /* apply logical operation */
+ func_select = s->gr[VGA_GFX_DATA_ROTATE] >> 3;
+ switch(func_select) {
+ case 0:
+ default:
+ /* nothing to do */
+ break;
+ case 1:
+ /* and */
+ val &= s->latch;
+ break;
+ case 2:
+ /* or */
+ val |= s->latch;
+ break;
+ case 3:
+ /* xor */
+ val ^= s->latch;
+ break;
+ }
+
+ /* apply bit mask */
+ bit_mask |= bit_mask << 8;
+ bit_mask |= bit_mask << 16;
+ val = (val & bit_mask) | (s->latch & ~bit_mask);
+
+do_write:
+ /* mask data according to sr[2] */
+ s->plane_updated |= mask; /* only used to detect font change */
+ write_mask = mask16[mask];
+ if (addr * sizeof(uint32_t) >= s->vram_size) {
+ return;
+ }
+ ((uint32_t *)s->vram_ptr)[addr] =
+ (((uint32_t *)s->vram_ptr)[addr] & ~write_mask) |
+ (val & write_mask);
+#ifdef DEBUG_VGA_MEM
+ printf("vga: latch: [0x" HWADDR_FMT_plx "] mask=0x%08x val=0x%08x\n",
+ addr * 4, write_mask, val);
+#endif
+ memory_region_set_dirty(&s->vram, addr << 2, sizeof(uint32_t));
}
typedef void *vga_draw_line_func(VGACommonState *s1, uint8_t *d,
--
2.43.0On 31/12/23 10:39, Paolo Bonzini wrote: > The next patch will reuse latched memory access in text modes. Start with > a patch that moves the latched access code out of the "if". > > Best reviewed with "git diff -b". > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > hw/display/vga.c | 211 ++++++++++++++++++++++++----------------------- > 1 file changed, 110 insertions(+), 101 deletions(-) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
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