I have computer science classes, we learn assembly using fasm, classes rely on win api, but i use linux so i've got approval to use external libraries. I've chose Raylib.
Problem is that I can't call LoadFont(Ex) without program segfaulting.
I tried to store structure in font by reserving 64 bytes, and tried to store pointer to the data before that, but no luck.
format ELF64
section ".data" writeable
screenWidth: dd 800
screenHeight: dd 600
windowTitle: db "raylib [text] example - font loading", 0
codepoints: times 512 dd 0
fontFile: db "km.ttf", 0
text1: db "Окей, Okay!", 0
text2: db "С Новым Годом!", 0
section ".bss"
font: rb 64
section '.text' executable
public _start
extrn printf
extrn _exit
extrn InitWindow
extrn WindowShouldClose
extrn CloseWindow
extrn BeginDrawing
extrn EndDrawing
extrn ClearBackground
extrn DrawText
extrn DrawTextEx
extrn LoadFontEx
extrn UnloadFont
_start:
mov rdi, 400
mov rsi, 300
mov rdx, windowTitle
call InitWindow
init_ascii:
mov rcx, 0x20 ; rcx is codepoints count
init_ascii_loop:
mov [codepoints + rcx - 0x20], rcx
inc rcx
cmp rcx, 127
jne init_ascii_loop
init_cyrillic:
mov rcx, 0x400 ; rcx is codepoints count
init_cyrillic_loop:
mov [codepoints + rcx - 0x400], rcx
inc rcx
cmp rcx, 0x6c1
jne init_cyrillic_loop
; Load the font
mov rdi, fontFile ; font file
mov rsi, 32 ; font size
mov rdx, codepoints ; codepoints
mov rcx, 211 ; codepoints count
call LoadFontEx
mov [font], rax
.again:
call WindowShouldClose
test rax, rax
jnz .over
call BeginDrawing
mov rdi, 0xFF181818
call ClearBackground
mov rdi, text1
mov rsi, 100
mov rdx, 100
mov rcx, 20
mov r8, 0xFFFFFFFF
call DrawText
; mov rdi, text1
; mov rsi, 100
; mov rdx, 100
; mov rcx, 20
; mov r8, 0xFFFFFFFF
; call DrawTextEx
call EndDrawing
jmp .again
.over:
call CloseWindow
mov rdi, 0
call _exit
I've figured it using this
Basically, function LoadFont stores new font on the stack instead of returning it as a value, that's why we pass rsp (register (for) stack pointer) into rdi
Later to call DrawTextEx we should have font structure loaded into rsp as the last data on stack, so that function can safely reference it (i think thats what happens on lines 68-73, if im wrong correct me please)
format ELF64
section ".data" writeable
screenWidth: dd 850
screenHeight: dd 300
windowTitle: db "Моя программа.", 0
fontFile: db '../assets/km.ttf', 0
text:
.message: db "Программировать наАссемблер на FASM — это классно!", 0
.xy: dd 100.0, 100.0
.fontSize: dd 30.0
.spacing: dd 0.0
; unicode
codepoints: dd 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 0, \
\ ; cyrillic
1024, 1025, 1026, 1027, 1028, 1029, 1030, 1031, 1032, 1033, 1034, 1035, 1036, 1037, 1038, 1039, 1040, 1041, 1042, 1043, 1044, 1045, 1046, 1047, 1048, 1049, 1050, 1051, 1052, 1053, 1054, 1055, 1056, 1057, 1058, 1059, 1060, 1061, 1062, 1063, 1064, 1065, 1066, 1067, 1068, 1069, 1070, 1071, 1072, 1073, 1074, 1075, 1076, 1077, 1078, 1079, 1080, 1081, 1082, 1083, 1084, 1085, 1086, 1087, 1088, 1089, 1090, 1091, 1092, 1093, 1094, 1095, 1096, 1097, 1098, 1099, 1100, 1101, 1102, 1103, 1104, 1105, 1106, 1107, 1108, 1109, 1110, 1111, 1112, 1113, 1114, 1115, 1116, 1117, 1118, 1119, 1120, 1121, 1122, 1123, 1124, 1125, 1126, 1127, 1128, 1129, 1130, 1131, 1132, 1133, 1134, 1135, 1136, 1137, 1138
section ".bss" writeable
font: rb 48
section '.text' executable
public _start
extrn printf
extrn _exit
extrn InitWindow
extrn WindowShouldClose
extrn CloseWindow
extrn BeginDrawing
extrn EndDrawing
extrn ClearBackground
extrn DrawTextEx
extrn LoadFontEx
extrn UnloadFont
_start:
mov rdi, [screenWidth]
mov rsi, [screenHeight]
mov rdx, windowTitle
call InitWindow
; load font
mov rdi, font
mov esi, fontFile ; move offset of "km.ttf" into esi
mov edx, 32 ; move 32 into edx
mov rcx, codepoints ; move address of codepoints into rcx
mov r8d, 211 ; move 211 into r8d
call LoadFontEx
.again:
call WindowShouldClose
test rax, rax
jnz .over
call BeginDrawing
mov rdi, 0xfffafafa ; a g b r
call ClearBackground
sub rsp, 48
movdqa xmm3, [font] ; tmp136, f
movups [rsp], xmm3 ; tmp136
movdqa xmm4, [font+16] ; tmp137, f
movups [rsp+16], xmm4 ; tmp137
movdqa xmm5, [font+32] ; tmp138, f
movups [rsp+32], xmm5 ; tmp138
mov edi, text.message
movq xmm0, [text.xy]
movss xmm1, [text.fontSize]
movss xmm2, [text.spacing]
mov esi, 0xff181818
call DrawTextEx
add rsp, 48
call EndDrawing
jmp .again
.over:
; unload font
sub rsp, 48
movdqa xmm3, [font]
movups [rsp], xmm3
movdqa xmm4, [font+16]
movups [rsp+16], xmm4
movdqa xmm5, [font+32]
movups [rsp+32], xmm5
call UnloadFont
add rsp, 48
; close window
call CloseWindow
mov rdi, 0
call _exit