145 lines
3.2 KiB
NASM
145 lines
3.2 KiB
NASM
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constant FONT_WIDTH(8)
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constant FONT_HEIGHT(16)
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constant FONT_SIZE16(FONT_WIDTH * FONT_HEIGHT * 2 * 95) // 0x5F00
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LoadFont16:
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// loads a 95-character, 8x16 font
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// as an RGB5A1 (16-bpp) image to the specified address.
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// a0: address to load font to (size: 0x5F00)
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li t9, FONT_SIZE16
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addu a1, a0, t9 // a1: end of output (exclusive)
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la a2, FONT // a2: start of input
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la a3, FONT + FONT.size // a3: end of input (exclusive)
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LoadFont16Loop:
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lhu t9, 0(a2)
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addiu a2, 2
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srl t1, t9, 12
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srl t2, t9, 8
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srl t3, t9, 4
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andi t4, t9, 0x0F
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andi t2, 0x0F
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andi t3, 0x0F
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if 0 {
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sll t1, 2
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sll t2, 2
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sll t3, 2
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sll t4, 2
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} else {
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// copy lsb to get the full 5-bit range of values.
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sll t5, t1, 1
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sll t6, t2, 1
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sll t7, t3, 1
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sll t8, t4, 1
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andi t1, 1
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andi t2, 1
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andi t3, 1
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andi t4, 1
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or t1, t5
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or t2, t6
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or t3, t7
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or t4, t8
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sll t1, 1
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sll t2, 1
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sll t3, 1
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sll t4, 1
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}
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sll t5, t1, 5
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sll t6, t2, 5
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sll t7, t3, 5
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sll t8, t4, 5
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or t1, t5
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or t2, t6
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or t3, t7
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or t4, t8
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sll t5, t1, 5
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sll t6, t2, 5
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sll t7, t3, 5
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sll t8, t4, 5
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or t1, t5
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or t2, t6
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or t3, t7
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or t4, t8
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ori t1, 1
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ori t2, 1
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ori t3, 1
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ori t4, 1
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sh t1, 0x0(a0)
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sh t2, 0x2(a0)
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sh t3, 0x4(a0)
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sh t4, 0x6(a0)
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bne a2, a3, LoadFont16Loop
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addiu a0, 0x8
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jr ra
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nop
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DrawChar16:
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// draws a 16-bpp character on-screen at the specified coordinates.
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// a0: font data address (same argument as LoadFont16)
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// a1: character (range: 32 to 126 inclusive)
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// a2: X, Y coordinate in pixels: X | Y << 16
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// a3: output image address
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// exit early if character is outside of valid range.
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subiu a1, 0x20
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bltz a1, DrawCharDone
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sltiu at, a1, 0x80 - 0x20
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beqz at, DrawCharDone
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lli t9, FONT_WIDTH * FONT_HEIGHT * 2 // delay slot
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multu a1, t9
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mflo t9
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addu a0, t9 // a0: character data address
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andi a1, a2, 0xFFFF // a1: X
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srl a2, 16 // a2: Y
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sll t0, a1, 1
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lli t9, WIDTH * 2
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multu a2, t9
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mflo t9
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addu a3, t0 // offset output by X
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addu a3, t9 // offset output by Y
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lli t9, FONT_HEIGHT // t9: rows remaining
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DrawChar16Loop:
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// character width hardcoded for 8.
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lhu t1, 0x0(a0)
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lhu t2, 0x2(a0)
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lhu t3, 0x4(a0)
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lhu t4, 0x6(a0)
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lhu t5, 0x8(a0)
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lhu t6, 0xA(a0)
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lhu t7, 0xC(a0)
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lhu t8, 0xE(a0)
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sh t1, 0x0(a3)
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sh t2, 0x2(a3)
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sh t3, 0x4(a3)
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sh t4, 0x6(a3)
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sh t5, 0x8(a3)
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sh t6, 0xA(a3)
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sh t7, 0xC(a3)
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sh t8, 0xE(a3)
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addiu a0, 0x10
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subiu t9, 1
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bnez t9, DrawChar16Loop
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addiu a3, WIDTH * 2
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DrawCharDone:
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jr ra
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nop
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insert FONT, "res/fonts/NotoSansMono-SemiCondensedMedium.16.i4"
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