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Apply A mask when loading into barrel shifter.

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This commit is contained in:
Thomas Harte 2021-10-26 20:02:28 -07:00
parent b4286bb42b
commit b10f5ab110
2 changed files with 44 additions and 42 deletions
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83
Machines/Amiga/Blitter.cpp
View File

@ -12,9 +12,9 @@
#include <cassert>
//#ifndef NDEBUG
//#define NDEBUG
//#endif
#ifndef NDEBUG
#define NDEBUG
#endif
#define LOG_PREFIX "[Blitter] "
#include "../../Outputs/Log.hpp"
@ -87,9 +87,9 @@ void Blitter::set_data(int channel, uint16_t value) {
// Ugh, backed myself into a corner. TODO: clean.
switch(channel) {
case 0: a_ = value; break;
case 1: b_ = value; break;
case 2: c_ = value; break;
case 0: a_data_ = value; break;
case 1: b_data_ = value; break;
case 2: c_data_ = value; break;
default: break;
}
}
@ -162,9 +162,9 @@ bool Blitter::advance() {
if(draw_) {
// TODO: patterned lines. Unclear what to do with the bit that comes out of b.
// Probably extend it to a full word?
c_ = ram_[pointer_[3] & ram_mask_];
c_data_ = ram_[pointer_[3] & ram_mask_];
ram_[pointer_[3] & ram_mask_] =
apply_minterm<uint16_t>(a_ >> shifts_[0], b_, c_, minterms_);
apply_minterm<uint16_t>(a_data_ >> shifts_[0], b_data_, c_data_, minterms_);
draw_ &= !one_dot_;
}
@ -219,45 +219,50 @@ bool Blitter::advance() {
// printf("*** [%d x %d]\n", width_, height_);
// Quick hack: do the entire action atomically.
if(channel_enables_[0]) a_ = 0;
if(channel_enables_[1]) b_ = 0;
if(channel_enables_[2]) c_ = 0;
a32_ = 0;
b32_ = 0;
for(int y = 0; y < height_; y++) {
for(int x = 0; x < width_; x++) {
if(channel_enables_[0]) {
a32_ = (a32_ << 16) | ram_[pointer_[0] & ram_mask_];
pointer_[0] += direction_;
uint16_t a_mask = 0xffff;
if(x == 0) a_mask &= a_mask_[0];
if(x == width_ - 1) a_mask &= a_mask_[1];
// The barrel shifter shifts to the right in ascending address mode,
// but to the left othrwise
if(!one_dot_) {
a_ = uint16_t(a32_ >> shifts_[0]);
} else {
// TODO: there must be a neater solution than this.
a_ = uint16_t(
(a32_ << shifts_[0]) |
(a32_ >> (32 - shifts_[0]))
);
}
if(channel_enables_[0]) {
a_data_ = ram_[pointer_[0] & ram_mask_];
pointer_[0] += direction_;
}
a32_ = (a32_ << 16) | (a_data_ & a_mask);
// The barrel shifter shifts to the right in ascending address mode,
// but to the left othrwise
if(!one_dot_) {
a_ = uint16_t(a32_ >> shifts_[0]);
} else {
// TODO: there must be a neater solution than this.
a_ = uint16_t(
(a32_ << shifts_[0]) |
(a32_ >> (32 - shifts_[0]))
);
}
if(channel_enables_[1]) {
b32_ = (b32_ << 16) | ram_[pointer_[1] & ram_mask_];
b_data_ = ram_[pointer_[1] & ram_mask_];
pointer_[1] += direction_;
}
b32_ = (b32_ << 16) | b_data_;
if(!one_dot_) {
b_ = uint16_t(b32_ >> shifts_[1]);
} else {
b_ = uint16_t(
(b32_ << shifts_[1]) |
(b32_ >> (32 - shifts_[1]))
);
}
if(!one_dot_) {
b_ = uint16_t(b32_ >> shifts_[1]);
} else {
b_ = uint16_t(
(b32_ << shifts_[1]) |
(b32_ >> (32 - shifts_[1]))
);
}
if(channel_enables_[2]) {
c_ = ram_[pointer_[2] & ram_mask_];
c_data_ = ram_[pointer_[2] & ram_mask_];
pointer_[2] += direction_;
}
@ -265,15 +270,11 @@ bool Blitter::advance() {
// if(!(lc&15)) printf("\n%06x: ", pointer_[3]);
// ++lc;
uint16_t a_mask = 0xffff;
if(x == 0) a_mask &= a_mask_[0];
if(x == width_ - 1) a_mask &= a_mask_[1];
ram_[pointer_[3] & ram_mask_] =
apply_minterm<uint16_t>(
a_ & a_mask, // TODO: is this properly-placed?
a_,
b_,
c_,
c_data_,
minterms_);
// printf("%04x ", ram_[pointer_[3] & ram_mask_]);

3
Machines/Amiga/Blitter.hpp
View File

@ -59,7 +59,8 @@ class Blitter: public DMADevice<4> {
uint8_t minterms_ = 0;
uint32_t a32_ = 0, b32_ = 0;
uint16_t a_ = 0, b_ = 0, c_ = 0;
uint16_t a_data_ = 0, b_data_ = 0, c_data_ = 0;
uint16_t a_ = 0, b_ = 0;
uint32_t modulos_[4]{};
};